51557720 has 32 divisors (see below), whose sum is σ = 121050720. Its totient is φ = 19726080.

The previous prime is 51557717. The next prime is 51557777. The reversal of 51557720 is 2775515.

It is a Smith number, since the sum of its digits (32) coincides with the sum of the digits of its prime factors.

It is a congruent number.

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, 27101 + ... + 28940.

It is an arithmetic number, because the mean of its divisors is an integer number (3782835).

Almost surely, 2^51557720 is an apocalyptic number.

It is an amenable number.

51557720 is an abundant number, since it is smaller than the sum of its proper divisors (69493000).

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

51557720 is a wasteful number, since it uses less digits than its factorization.

51557720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56075 (or 56071 counting only the distinct ones).

The product of its (nonzero) digits is 12250, while the sum is 32.

The square root of 51557720 is about 7180.3704639803. The cubic root of 51557720 is about 372.1898864842.

The spelling of 51557720 in words is "fifty-one million, five hundred fifty-seven thousand, seven hundred twenty".