21465542631 has 16 divisors (see below), whose sum is σ = 31478114304. Its totient is φ = 12928509024.

The previous prime is 21465542597. The next prime is 21465542633. The reversal of 21465542631 is 13624556412.

It is not a de Polignac number, because 21465542631 - 2¹³ = 21465534439 is a prime.

It is a super-2 number, since 2×21465542631² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a self number, because there is not a number n which added to its sum of digits gives 21465542631.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21465542633) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5853471 + ... + 5857136.

It is an arithmetic number, because the mean of its divisors is an integer number (1967382144).

Almost surely, 2^21465542631 is an apocalyptic number.

21465542631 is a deficient number, since it is larger than the sum of its proper divisors (10012571673).

21465542631 is a wasteful number, since it uses less digits than its factorization.

21465542631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11710670.

The product of its digits is 172800, while the sum is 39.

The spelling of 21465542631 in words is "twenty-one billion, four hundred sixty-five million, five hundred forty-two thousand, six hundred thirty-one".