51899940 has 144 divisors (see below), whose sum is σ = 166944960. Its totient is φ = 13530240.

The previous prime is 51899923. The next prime is 51899971. The reversal of 51899940 is 4999815.

51899940 is a `hidden beast` number, since 518 + 9 + 99 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 286650 + ... + 286830.

It is an arithmetic number, because the mean of its divisors is an integer number (1159340).

Almost surely, 2^51899940 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51899940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83472480).

51899940 is an abundant number, since it is smaller than the sum of its proper divisors (115045020).

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

51899940 is a wasteful number, since it uses less digits than its factorization.

51899940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 264 (or 250 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 45.

The square root of 51899940 is about 7204.1612974725. The cubic root of 51899940 is about 373.0115548654.

It can be divided in two parts, 5189 and 9940, that added together give a square (15129 = 123²).

The spelling of 51899940 in words is "fifty-one million, eight hundred ninety-nine thousand, nine hundred forty".