21531112004 has 12 divisors (see below), whose sum is σ = 38133415824. Its totient is φ = 10635850344.

The previous prime is 21531112003. The next prime is 21531112007. The reversal of 21531112004 is 40021113512.

It is not an unprimeable number, because it can be changed into a prime (21531112003) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32426042 + ... + 32426705.

It is an arithmetic number, because the mean of its divisors is an integer number (3177784652).

Almost surely, 2^21531112004 is an apocalyptic number.

It is an amenable number.

21531112004 is a deficient number, since it is larger than the sum of its proper divisors (16602303820).

21531112004 is a wasteful number, since it uses less digits than its factorization.

21531112004 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64852834 (or 64852832 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

Adding to 21531112004 its reverse (40021113512), we get a palindrome (61552225516).

The spelling of 21531112004 in words is "twenty-one billion, five hundred thirty-one million, one hundred twelve thousand, four".