21489597990 has 48 divisors (see below), whose sum is σ = 63854807328. Its totient is φ = 4911907968.

The previous prime is 21489597971. The next prime is 21489598007. The reversal of 21489597990 is 9979598412.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17054607 + ... + 17055866.

It is an arithmetic number, because the mean of its divisors is an integer number (1330308486).

Almost surely, 2^21489597990 is an apocalyptic number.

21489597990 is an abundant number, since it is smaller than the sum of its proper divisors (42365209338).

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

21489597990 is a wasteful number, since it uses less digits than its factorization.

21489597990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34110493 (or 34110490 counting only the distinct ones).

The product of its (nonzero) digits is 14696640, while the sum is 63.

The spelling of 21489597990 in words is "twenty-one billion, four hundred eighty-nine million, five hundred ninety-seven thousand, nine hundred ninety".