20808740 has 24 divisors (see below), whose sum is σ = 43804152. Its totient is φ = 8303360.

The previous prime is 20808737. The next prime is 20808761. The reversal of 20808740 is 4780802.

It can be written as a sum of positive squares in 4 ways, for example, as 215296 + 20593444 = 464^2 + 4538^2 .

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, 9422 + ... + 11418.

It is an arithmetic number, because the mean of its divisors is an integer number (1825173).

Almost surely, 2^20808740 is an apocalyptic number.

20808740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20808740 is an abundant number, since it is smaller than the sum of its proper divisors (22995412).

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

20808740 is a wasteful number, since it uses less digits than its factorization.

20808740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2527 (or 2525 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 29.

The square root of 20808740 is about 4561.6597856482. The cubic root of 20808740 is about 275.0522875782.

The spelling of 20808740 in words is "twenty million, eight hundred eight thousand, seven hundred forty".