51723440 has 20 divisors (see below), whose sum is σ = 120257184. Its totient is φ = 20689344.

The previous prime is 51723439. The next prime is 51723457. The reversal of 51723440 is 4432715.

It is a tau number, because it is divible by the number of its divisors (20).

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, 323192 + ... + 323351.

Almost surely, 2^51723440 is an apocalyptic number.

It is an amenable number.

51723440 is an abundant number, since it is smaller than the sum of its proper divisors (68533744).

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

51723440 is a wasteful number, since it uses less digits than its factorization.

51723440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 646556 (or 646550 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 26.

The square root of 51723440 is about 7191.9010004310. The cubic root of 51723440 is about 372.5882318808.

The spelling of 51723440 in words is "fifty-one million, seven hundred twenty-three thousand, four hundred forty".