21212523278856 has 1280 divisors, whose sum is σ = 78574843200000. Its totient is φ = 5300063653248.

The previous prime is 21212523278839. The next prime is 21212523278857. The reversal of 21212523278856 is 65887232521212.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

21212523278856 is a `hidden beast` number, since 2 + 1 + 2 + 12 + 523 + 27 + 8 + 85 + 6 = 666.

It is a super-2 number, since 2×21212523278856² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a taxicab number since it can be written as a sum of two cubes in more than one way. Here 21212523278856 = 3458³ + 27664³ = 15561³ + 25935³.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212523278857) by changing a digit.

It is a polite number, since it can be written in 319 ways as a sum of consecutive naturals, for example, 1116448593615 + ... + 1116448593633.

It is an arithmetic number, because the mean of its divisors is an integer number (61386596250).

Almost surely, 2^{21212523278856} is an apocalyptic number.

21212523278856 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21212523278856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39287421600000).

21212523278856 is an abundant number, since it is smaller than the sum of its proper divisors (57362319921144).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21212523278856 is an frugal number, since it uses more digits than its factorization.

21212523278856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151 (or 44 counting only the distinct ones).

The product of its digits is 6451200, while the sum is 54.

The spelling of 21212523278856 in words is "twenty-one trillion, two hundred twelve billion, five hundred twenty-three million, two hundred seventy-eight thousand, eight hundred fifty-six".