51591331 has 4 divisors (see below), whose sum is σ = 56281464. Its totient is φ = 46901200.

The previous prime is 51591317. The next prime is 51591343. The reversal of 51591331 is 13319515.

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 51591331 - 2¹¹ = 51589283 is a prime.

It is a super-2 number, since 2×51591331² = 5323330868703122, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 51591331.

It is not an unprimeable number, because it can be changed into a prime (51591391) 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, 2345050 + ... + 2345071.

It is an arithmetic number, because the mean of its divisors is an integer number (14070366).

Almost surely, 2^51591331 is an apocalyptic number.

51591331 is a deficient number, since it is larger than the sum of its proper divisors (4690133).

51591331 is a wasteful number, since it uses less digits than its factorization.

51591331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4690132.

The product of its digits is 2025, while the sum is 28.

The square root of 51591331 is about 7182.7105607841. The cubic root of 51591331 is about 372.2707470347.

The spelling of 51591331 in words is "fifty-one million, five hundred ninety-one thousand, three hundred thirty-one".