51755721 has 8 divisors (see below), whose sum is σ = 69355200. Its totient is φ = 34330032.

The previous prime is 51755659. The next prime is 51755731. The reversal of 51755721 is 12755715.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 51755721 - 2⁶ = 51755657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51755731) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42750 + ... + 43943.

It is an arithmetic number, because the mean of its divisors is an integer number (8669400).

Almost surely, 2^51755721 is an apocalyptic number.

It is an amenable number.

51755721 is a deficient number, since it is larger than the sum of its proper divisors (17599479).

51755721 is a wasteful number, since it uses less digits than its factorization.

51755721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86895.

The product of its digits is 12250, while the sum is 33.

The square root of 51755721 is about 7194.1449109675. The cubic root of 51755721 is about 372.6657274961.

The spelling of 51755721 in words is "fifty-one million, seven hundred fifty-five thousand, seven hundred twenty-one".