20918540 has 24 divisors (see below), whose sum is σ = 44146032. Its totient is φ = 8326080.

The previous prime is 20918533. The next prime is 20918567. The reversal of 20918540 is 4581902.

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, 1742 + ... + 6698.

It is an arithmetic number, because the mean of its divisors is an integer number (1839418).

Almost surely, 2^20918540 is an apocalyptic number.

20918540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20918540 is an abundant number, since it is smaller than the sum of its proper divisors (23227492).

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

20918540 is a wasteful number, since it uses less digits than its factorization.

20918540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5177 (or 5175 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 20918540 is about 4573.6790442706. The cubic root of 20918540 is about 275.5352221045.

The spelling of 20918540 in words is "twenty million, nine hundred eighteen thousand, five hundred forty".