20513988 has 36 divisors (see below), whose sum is σ = 56569968. Its totient is φ = 6216240.

The previous prime is 20513963. The next prime is 20513989. The reversal of 20513988 is 88931502.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (20513989) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25506 + ... + 26297.

It is an arithmetic number, because the mean of its divisors is an integer number (1571388).

Almost surely, 2^20513988 is an apocalyptic number.

It is an amenable number.

20513988 is an abundant number, since it is smaller than the sum of its proper divisors (36055980).

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

20513988 is a wasteful number, since it uses less digits than its factorization.

20513988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51824 (or 51819 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 20513988 is about 4529.2370218393. The cubic root of 20513988 is about 273.7474185032.

The spelling of 20513988 in words is "twenty million, five hundred thirteen thousand, nine hundred eighty-eight".