20915140 has 24 divisors (see below), whose sum is σ = 44378712. Its totient is φ = 8279040.

The previous prime is 20915123. The next prime is 20915179. The reversal of 20915140 is 4151902.

It can be written as a sum of positive squares in 4 ways, for example, as 719104 + 20196036 = 848^2 + 4494^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3451 + ... + 7330.

It is an arithmetic number, because the mean of its divisors is an integer number (1849113).

Almost surely, 2^20915140 is an apocalyptic number.

20915140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20915140 is an abundant number, since it is smaller than the sum of its proper divisors (23463572).

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

20915140 is a wasteful number, since it uses less digits than its factorization.

20915140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10887 (or 10885 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 20915140 is about 4573.3073371467. The cubic root of 20915140 is about 275.5202932341.

The spelling of 20915140 in words is "twenty million, nine hundred fifteen thousand, one hundred forty".