21256043016456 has 96 divisors (see below), whose sum is σ = 57955946419800. Its totient is φ = 7037806970880.

The previous prime is 21256043016449. The next prime is 21256043016487. The reversal of 21256043016456 is 65461034065212.

21256043016456 is a `hidden beast` number, since 2 + 1 + 2 + 5 + 6 + 0 + 430 + 164 + 56 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 16968385332900 + 4287657683556 = 4119270^2 + 2070666^2 .

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 23 ways as a sum of consecutive naturals, for example, 5175390 + ... + 8324466.

Almost surely, 2^{21256043016456} is an apocalyptic number.

It is an amenable number.

21256043016456 is an abundant number, since it is smaller than the sum of its proper divisors (36699903403344).

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

21256043016456 is a wasteful number, since it uses less digits than its factorization.

21256043016456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3149719 (or 3149712 counting only the distinct ones).

The product of its (nonzero) digits is 1036800, while the sum is 45.

The spelling of 21256043016456 in words is "twenty-one trillion, two hundred fifty-six billion, forty-three million, sixteen thousand, four hundred fifty-six".