21503532051 has 16 divisors (see below), whose sum is σ = 31948905600. Its totient is φ = 14294368584.

The previous prime is 21503532041. The next prime is 21503532097. The reversal of 21503532051 is 15023530512.

It is a happy number.

It is not a de Polignac number, because 21503532051 - 2⁵ = 21503532019 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21503532041) 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, 1138221 + ... + 1156958.

It is an arithmetic number, because the mean of its divisors is an integer number (1996806600).

Almost surely, 2^21503532051 is an apocalyptic number.

21503532051 is a deficient number, since it is larger than the sum of its proper divisors (10445373549).

21503532051 is a wasteful number, since it uses less digits than its factorization.

21503532051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2295535 (or 2295529 counting only the distinct ones).

The product of its (nonzero) digits is 4500, while the sum is 27.

The spelling of 21503532051 in words is "twenty-one billion, five hundred three million, five hundred thirty-two thousand, fifty-one".