21631504238 has 4 divisors (see below), whose sum is σ = 32447256360. Its totient is φ = 10815752118.

The previous prime is 21631504207. The next prime is 21631504249. The reversal of 21631504238 is 83240513612.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×21631504238² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21631504198 and 21631504207.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5407876058 + ... + 5407876061.

It is an arithmetic number, because the mean of its divisors is an integer number (8111814090).

Almost surely, 2^21631504238 is an apocalyptic number.

21631504238 is a deficient number, since it is larger than the sum of its proper divisors (10815752122).

21631504238 is a wasteful number, since it uses less digits than its factorization.

21631504238 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10815752121.

The product of its (nonzero) digits is 34560, while the sum is 35.

The spelling of 21631504238 in words is "twenty-one billion, six hundred thirty-one million, five hundred four thousand, two hundred thirty-eight".