20399988 has 48 divisors (see below), whose sum is σ = 56770560. Its totient is φ = 5574624.

The previous prime is 20399969. The next prime is 20399993. The reversal of 20399988 is 88999302.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3348 + ... + 7211.

It is an arithmetic number, because the mean of its divisors is an integer number (1182720).

Almost surely, 2^20399988 is an apocalyptic number.

20399988 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

20399988 is an abundant number, since it is smaller than the sum of its proper divisors (36370572).

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

20399988 is a wasteful number, since it uses less digits than its factorization.

20399988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10596 (or 10594 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 48.

The square root of 20399988 is about 4516.6345878320. The cubic root of 20399988 is about 273.2393880331.

The spelling of 20399988 in words is "twenty million, three hundred ninety-nine thousand, nine hundred eighty-eight".