21356513451 has 48 divisors (see below), whose sum is σ = 37985438400. Its totient is φ = 11259544320.

The previous prime is 21356513419. The next prime is 21356513501. The reversal of 21356513451 is 15431565312.

21356513451 is a `hidden beast` number, since 2 + 13 + 565 + 1 + 34 + 51 = 666.

It is not a de Polignac number, because 21356513451 - 2⁵ = 21356513419 is a prime.

It is a super-2 number, since 2×21356513451² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21356513401) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2141625 + ... + 2151573.

It is an arithmetic number, because the mean of its divisors is an integer number (791363300).

Almost surely, 2^21356513451 is an apocalyptic number.

21356513451 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21356513451 is a deficient number, since it is larger than the sum of its proper divisors (16628924949).

21356513451 is a wasteful number, since it uses less digits than its factorization.

21356513451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12596 (or 12593 counting only the distinct ones).

The product of its digits is 54000, while the sum is 36.

The spelling of 21356513451 in words is "twenty-one billion, three hundred fifty-six million, five hundred thirteen thousand, four hundred fifty-one".