21221355255012 has 192 divisors, whose sum is σ = 60861343334400. Its totient is φ = 6340624738560.

The previous prime is 21221355254971. The next prime is 21221355255019. The reversal of 21221355255012 is 21055255312212.

21221355255012 is a `hidden beast` number, since 2 + 1 + 2 + 21 + 35 + 52 + 550 + 1 + 2 = 666.

It is a super-2 number, since 2×21221355255012² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21221355255019) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 287800093 + ... + 287873819.

It is an arithmetic number, because the mean of its divisors is an integer number (316986163200).

Almost surely, 2^{21221355255012} is an apocalyptic number.

21221355255012 is a gapful number since it is divisible by the number (22) 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 21221355255012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30430671667200).

21221355255012 is an abundant number, since it is smaller than the sum of its proper divisors (39639988079388).

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

21221355255012 is a wasteful number, since it uses less digits than its factorization.

21221355255012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77143 (or 77135 counting only the distinct ones).

The product of its (nonzero) digits is 60000, while the sum is 36.

The spelling of 21221355255012 in words is "twenty-one trillion, two hundred twenty-one billion, three hundred fifty-five million, two hundred fifty-five thousand, twelve".