51165691 has 4 divisors (see below), whose sum is σ = 51672384. Its totient is φ = 50659000.

The previous prime is 51165679. The next prime is 51165701. The reversal of 51165691 is 19656115.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 51165691 - 2⁵ = 51165659 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51165661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 253195 + ... + 253396.

It is an arithmetic number, because the mean of its divisors is an integer number (12918096).

Almost surely, 2^51165691 is an apocalyptic number.

51165691 is a deficient number, since it is larger than the sum of its proper divisors (506693).

51165691 is a wasteful number, since it uses less digits than its factorization.

51165691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 506692.

The product of its digits is 8100, while the sum is 34.

The square root of 51165691 is about 7153.0197119818. The cubic root of 51165691 is about 371.2441463478.

The spelling of 51165691 in words is "fifty-one million, one hundred sixty-five thousand, six hundred ninety-one".