21535232256 has 108 divisors (see below), whose sum is σ = 65743937532. Its totient is φ = 6756139008.

The previous prime is 21535232219. The next prime is 21535232291. The reversal of 21535232256 is 65223253512.

21535232256 is a `hidden beast` number, since 21 + 5 + 352 + 32 + 256 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 12273094656 + 9262137600 = 110784^2 + 96240^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 21535232256.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 235741 + ... + 314076.

Almost surely, 2^21535232256 is an apocalyptic number.

It is an amenable number.

21535232256 is an abundant number, since it is smaller than the sum of its proper divisors (44208705276).

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

21535232256 is a wasteful number, since it uses less digits than its factorization.

21535232256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 549856 (or 549839 counting only the distinct ones).

The product of its digits is 108000, while the sum is 36.

Adding to 21535232256 its reverse (65223253512), we get a palindrome (86758485768).

The spelling of 21535232256 in words is "twenty-one billion, five hundred thirty-five million, two hundred thirty-two thousand, two hundred fifty-six".