21255411936 has 192 divisors, whose sum is σ = 62123023872. Its totient is φ = 6309120000.

The previous prime is 21255411907. The next prime is 21255411973. The reversal of 21255411936 is 63911455212.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21255411894 and 21255411903.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 20032846 + ... + 20033906.

It is an arithmetic number, because the mean of its divisors is an integer number (323557416).

Almost surely, 2^21255411936 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21255411936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31061511936).

21255411936 is an abundant number, since it is smaller than the sum of its proper divisors (40867611936).

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

21255411936 is a wasteful number, since it uses less digits than its factorization.

21255411936 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1457 (or 1449 counting only the distinct ones).

The product of its digits is 64800, while the sum is 39.

The spelling of 21255411936 in words is "twenty-one billion, two hundred fifty-five million, four hundred eleven thousand, nine hundred thirty-six".