20515985 has 16 divisors (see below), whose sum is σ = 28430976. Its totient is φ = 13920768.

The previous prime is 20515967. The next prime is 20516009. The reversal of 20515985 is 58951502.

It is a cyclic number.

It is not a de Polignac number, because 20515985 - 2⁶ = 20515921 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a Curzon 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, 374 + ... + 6416.

It is an arithmetic number, because the mean of its divisors is an integer number (1776936).

Almost surely, 2^20515985 is an apocalyptic number.

It is an amenable number.

20515985 is a deficient number, since it is larger than the sum of its proper divisors (7914991).

20515985 is an equidigital number, since it uses as much as digits as its factorization.

20515985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6152.

The product of its (nonzero) digits is 18000, while the sum is 35.

The square root of 20515985 is about 4529.4574730314. The cubic root of 20515985 is about 273.7563011553.

The spelling of 20515985 in words is "twenty million, five hundred fifteen thousand, nine hundred eighty-five".