20711840 has 24 divisors (see below), whose sum is σ = 48932100. Its totient is φ = 8284672.

The previous prime is 20711839. The next prime is 20711861. The reversal of 20711840 is 4811702.

It can be written as a sum of positive squares in 2 ways, for example, as 17875984 + 2835856 = 4228^2 + 1684^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64565 + ... + 64884.

Almost surely, 2^20711840 is an apocalyptic number.

20711840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20711840 is an abundant number, since it is smaller than the sum of its proper divisors (28220260).

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

20711840 is a wasteful number, since it uses less digits than its factorization.

20711840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129464 (or 129456 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 23.

The square root of 20711840 is about 4551.0262578895. The cubic root of 20711840 is about 274.6246780737.

The spelling of 20711840 in words is "twenty million, seven hundred eleven thousand, eight hundred forty".