21531204523416 has 32 divisors (see below), whose sum is σ = 61517727210240. Its totient is φ = 6151772720928.

The previous prime is 21531204523267. The next prime is 21531204523417. The reversal of 21531204523416 is 61432540213512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21531204523417) 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, 64080965676 + ... + 64080966011.

It is an arithmetic number, because the mean of its divisors is an integer number (1922428975320).

Almost surely, 2^{21531204523416} is an apocalyptic number.

It is an amenable number.

21531204523416 is an abundant number, since it is smaller than the sum of its proper divisors (39986522686824).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21531204523416 is a wasteful number, since it uses less digits than its factorization.

21531204523416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128161931703 (or 128161931699 counting only the distinct ones).

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

Adding to 21531204523416 its reverse (61432540213512), we get a palindrome (82963744736928).

The spelling of 21531204523416 in words is "twenty-one trillion, five hundred thirty-one billion, two hundred four million, five hundred twenty-three thousand, four hundred sixteen".