21522531987 has 48 divisors (see below), whose sum is σ = 34189635168. Its totient is φ = 12938365440.

The previous prime is 21522531971. The next prime is 21522531991. The reversal of 21522531987 is 78913522512.

21522531987 is a `hidden beast` number, since 2 + 1 + 5 + 22 + 531 + 98 + 7 = 666.

It is not a de Polignac number, because 21522531987 - 2⁴ = 21522531971 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21522531287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 14811753 + ... + 14813205.

It is an arithmetic number, because the mean of its divisors is an integer number (712284066).

Almost surely, 2^21522531987 is an apocalyptic number.

21522531987 is a deficient number, since it is larger than the sum of its proper divisors (12667103181).

21522531987 is a wasteful number, since it uses less digits than its factorization.

21522531987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2580 (or 2577 counting only the distinct ones).

The product of its digits is 302400, while the sum is 45.

The spelling of 21522531987 in words is "twenty-one billion, five hundred twenty-two million, five hundred thirty-one thousand, nine hundred eighty-seven".