21543252651 has 12 divisors (see below), whose sum is σ = 31120553880. Its totient is φ = 14361004320.

The previous prime is 21543252617. The next prime is 21543252659. The reversal of 21543252651 is 15625234512.

21543252651 is a `hidden beast` number, since 2 + 1 + 54 + 32 + 526 + 51 = 666.

It is not a de Polignac number, because 21543252651 - 2¹⁰ = 21543251627 is a prime.

It is a super-2 number, since 2×21543252651² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21543252659) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 28780 + ... + 209558.

It is an arithmetic number, because the mean of its divisors is an integer number (2593379490).

Almost surely, 2^21543252651 is an apocalyptic number.

21543252651 is a deficient number, since it is larger than the sum of its proper divisors (9577301229).

21543252651 is a wasteful number, since it uses less digits than its factorization.

21543252651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194026 (or 194023 counting only the distinct ones).

The product of its digits is 72000, while the sum is 36.

The spelling of 21543252651 in words is "twenty-one billion, five hundred forty-three million, two hundred fifty-two thousand, six hundred fifty-one".