51811940 has 12 divisors (see below), whose sum is σ = 108805116. Its totient is φ = 20724768.

The previous prime is 51811927. The next prime is 51811961. The reversal of 51811940 is 4911815.

It can be written as a sum of positive squares in 2 ways, for example, as 8988004 + 42823936 = 2998^2 + 6544^2 .

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, 1295279 + ... + 1295318.

It is an arithmetic number, because the mean of its divisors is an integer number (9067093).

Almost surely, 2^51811940 is an apocalyptic number.

It is an amenable number.

51811940 is an abundant number, since it is smaller than the sum of its proper divisors (56993176).

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

51811940 is a wasteful number, since it uses less digits than its factorization.

51811940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2590606 (or 2590604 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 29.

The square root of 51811940 is about 7198.0511251310. The cubic root of 51811940 is about 372.8006131527.

The spelling of 51811940 in words is "fifty-one million, eight hundred eleven thousand, nine hundred forty".