51699840 has 64 divisors (see below), whose sum is σ = 164799360. Its totient is φ = 13786112.

The previous prime is 51699821. The next prime is 51699887. The reversal of 51699840 is 4899615.

It is a tau number, because it is divible by the number of its divisors (64).

It is a junction number, because it is equal to n+sod(n) for n = 51699792 and 51699801.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11544 + ... + 15383.

It is an arithmetic number, because the mean of its divisors is an integer number (2574990).

Almost surely, 2^51699840 is an apocalyptic number.

It is an amenable number.

51699840 is an abundant number, since it is smaller than the sum of its proper divisors (113099520).

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

51699840 is a wasteful number, since it uses less digits than its factorization.

51699840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26949 (or 26937 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 42.

The square root of 51699840 is about 7190.2600787454. The cubic root of 51699840 is about 372.5315559652.

The spelling of 51699840 in words is "fifty-one million, six hundred ninety-nine thousand, eight hundred forty".