51715991 has 8 divisors (see below), whose sum is σ = 52376064. Its totient is φ = 51059160.

The previous prime is 51715987. The next prime is 51716003. The reversal of 51715991 is 19951715.

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

It is not a de Polignac number, because 51715991 - 2² = 51715987 is a prime.

It is a super-2 number, since 2×51715991² = 5349087450224162, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51715591) 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, 49646 + ... + 50676.

It is an arithmetic number, because the mean of its divisors is an integer number (6547008).

Almost surely, 2^51715991 is an apocalyptic number.

51715991 is a deficient number, since it is larger than the sum of its proper divisors (660073).

51715991 is a wasteful number, since it uses less digits than its factorization.

51715991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1621.

The product of its digits is 14175, while the sum is 38.

The square root of 51715991 is about 7191.3831075809. The cubic root of 51715991 is about 372.5703448069.

The spelling of 51715991 in words is "fifty-one million, seven hundred fifteen thousand, nine hundred ninety-one".