20399507988 has 12 divisors (see below), whose sum is σ = 47598852000. Its totient is φ = 6799835992.

The previous prime is 20399507977. The next prime is 20399508001. The reversal of 20399507988 is 88970599302.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×20399507988² (a number of 21 digits) contains 22 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, 849979488 + ... + 849979511.

It is an arithmetic number, because the mean of its divisors is an integer number (3966571000).

Almost surely, 2^20399507988 is an apocalyptic number.

It is an amenable number.

20399507988 is an abundant number, since it is smaller than the sum of its proper divisors (27199344012).

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

20399507988 is a wasteful number, since it uses less digits than its factorization.

20399507988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1699959006 (or 1699959004 counting only the distinct ones).

The product of its (nonzero) digits is 9797760, while the sum is 60.

The spelling of 20399507988 in words is "twenty billion, three hundred ninety-nine million, five hundred seven thousand, nine hundred eighty-eight".