20311840 has 24 divisors (see below), whose sum is σ = 47987100. Its totient is φ = 8124672.

The previous prime is 20311831. The next prime is 20311859. The reversal of 20311840 is 4811302.

It can be written as a sum of positive squares in 2 ways, for example, as 18558864 + 1752976 = 4308^2 + 1324^2 .

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 3 ways as a sum of consecutive naturals, for example, 63315 + ... + 63634.

Almost surely, 2^20311840 is an apocalyptic number.

20311840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20311840 is an abundant number, since it is smaller than the sum of its proper divisors (27675260).

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

20311840 is a wasteful number, since it uses less digits than its factorization.

20311840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126964 (or 126956 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 20311840 is about 4506.8658733093. The cubic root of 20311840 is about 272.8452655772.

The spelling of 20311840 in words is "twenty million, three hundred eleven thousand, eight hundred forty".