21522031521 has 16 divisors (see below), whose sum is σ = 28997408640. Its totient is φ = 14197507200.

The previous prime is 21522031513. The next prime is 21522031537. The reversal of 21522031521 is 12513022512.

It is not a de Polignac number, because 21522031521 - 2³ = 21522031513 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21522031491 and 21522031500.

It is not an unprimeable number, because it can be changed into a prime (21522031561) 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, 510900 + ... + 551418.

It is an arithmetic number, because the mean of its divisors is an integer number (1812338040).

Almost surely, 2^21522031521 is an apocalyptic number.

It is an amenable number.

21522031521 is a deficient number, since it is larger than the sum of its proper divisors (7475377119).

21522031521 is a wasteful number, since it uses less digits than its factorization.

21522031521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42376.

The product of its (nonzero) digits is 1200, while the sum is 24.

Subtracting from 21522031521 its reverse (12513022512), we obtain a palindrome (9009009009).

The spelling of 21522031521 in words is "twenty-one billion, five hundred twenty-two million, thirty-one thousand, five hundred twenty-one".