20928986 has 16 divisors (see below), whose sum is σ = 34128864. Its totient is φ = 9567984.

The previous prime is 20928979. The next prime is 20929001. The reversal of 20928986 is 68982902.

20928986 = 286² + 287² + ... + 441².

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 980 + ... + 6543.

It is an arithmetic number, because the mean of its divisors is an integer number (2133054).

Almost surely, 2^20928986 is an apocalyptic number.

20928986 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

20928986 is a deficient number, since it is larger than the sum of its proper divisors (13199878).

20928986 is a wasteful number, since it uses less digits than its factorization.

20928986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7645.

The product of its (nonzero) digits is 124416, while the sum is 44.

The square root of 20928986 is about 4574.8208708101. The cubic root of 20928986 is about 275.5810787459.

The spelling of 20928986 in words is "twenty million, nine hundred twenty-eight thousand, nine hundred eighty-six".