21526643531 has 8 divisors (see below), whose sum is σ = 22033608960. Its totient is φ = 21019966632.

The previous prime is 21526643507. The next prime is 21526643543. The reversal of 21526643531 is 13534662512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21526643531 - 2²² = 21522449227 is a prime.

It is a super-2 number, since 2×21526643531² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21526643591) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 82706 + ... + 223368.

It is an arithmetic number, because the mean of its divisors is an integer number (2754201120).

Almost surely, 2^21526643531 is an apocalyptic number.

21526643531 is a deficient number, since it is larger than the sum of its proper divisors (506965429).

21526643531 is a wasteful number, since it uses less digits than its factorization.

21526643531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144265.

The product of its digits is 129600, while the sum is 38.

The spelling of 21526643531 in words is "twenty-one billion, five hundred twenty-six million, six hundred forty-three thousand, five hundred thirty-one".