21021186791880 has 384 divisors, whose sum is σ = 74990151475200. Its totient is φ = 5064592704000.

The previous prime is 21021186791873. The next prime is 21021186791887. The reversal of 21021186791880 is 8819768112012.

21021186791880 is a `hidden beast` number, since 210 + 2 + 1 + 186 + 79 + 188 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (21021186791873) and next prime (21021186791887).

It is a super-2 number, since 2×21021186791880² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21021186791887) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1351750105 + ... + 1351765655.

It is an arithmetic number, because the mean of its divisors is an integer number (195286852800).

Almost surely, 2^{21021186791880} is an apocalyptic number.

21021186791880 is a gapful number since it is divisible by the number (20) 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 21021186791880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37495075737600).

21021186791880 is an abundant number, since it is smaller than the sum of its proper divisors (53968964683320).

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

21021186791880 is a wasteful number, since it uses less digits than its factorization.

21021186791880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17665 (or 17658 counting only the distinct ones).

The product of its (nonzero) digits is 774144, while the sum is 54.

The spelling of 21021186791880 in words is "twenty-one trillion, twenty-one billion, one hundred eighty-six million, seven hundred ninety-one thousand, eight hundred eighty".