20918986 has 32 divisors (see below), whose sum is σ = 36334080. Its totient is φ = 8942400.

The previous prime is 20918971. The next prime is 20918999. The reversal of 20918986 is 68981902.

It is a happy 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, 24820 + ... + 25648.

It is an arithmetic number, because the mean of its divisors is an integer number (1135440).

Almost surely, 2^20918986 is an apocalyptic number.

20918986 is a deficient number, since it is larger than the sum of its proper divisors (15415094).

20918986 is a wasteful number, since it uses less digits than its factorization.

20918986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 910.

The product of its (nonzero) digits is 62208, while the sum is 43.

The square root of 20918986 is about 4573.7278012580. The cubic root of 20918986 is about 275.5371803010.

It can be divided in two parts, 20918 and 986, that added together give a square (21904 = 148²).

The spelling of 20918986 in words is "twenty million, nine hundred eighteen thousand, nine hundred eighty-six".