21522531988 has 12 divisors (see below), whose sum is σ = 37713929652. Its totient is φ = 10747123520.

The previous prime is 21522531971. The next prime is 21522531991. The reversal of 21522531988 is 88913522512.

It can be written as a sum of positive squares in 2 ways, for example, as 11199565584 + 10322966404 = 105828^2 + 101602^2 .

It is a super-3 number, since 3×21522531988³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3532195 + ... + 3538282.

It is an arithmetic number, because the mean of its divisors is an integer number (3142827471).

Almost surely, 2^21522531988 is an apocalyptic number.

It is an amenable number.

21522531988 is a deficient number, since it is larger than the sum of its proper divisors (16191397664).

21522531988 is a wasteful number, since it uses less digits than its factorization.

21522531988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7071242 (or 7071240 counting only the distinct ones).

The product of its digits is 345600, while the sum is 46.

The spelling of 21522531988 in words is "twenty-one billion, five hundred twenty-two million, five hundred thirty-one thousand, nine hundred eighty-eight".