51311515 has 4 divisors (see below), whose sum is σ = 61573824. Its totient is φ = 41049208.

The previous prime is 51311501. The next prime is 51311537. The reversal of 51311515 is 51511315.

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 51311515 - 2⁵ = 51311483 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5131147 + ... + 5131156.

It is an arithmetic number, because the mean of its divisors is an integer number (15393456).

Almost surely, 2^51311515 is an apocalyptic number.

51311515 is a deficient number, since it is larger than the sum of its proper divisors (10262309).

51311515 is a wasteful number, since it uses less digits than its factorization.

51311515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10262308.

The product of its digits is 375, while the sum is 22.

The square root of 51311515 is about 7163.2056371432. The cubic root of 51311515 is about 371.5964980669.

The spelling of 51311515 in words is "fifty-one million, three hundred eleven thousand, five hundred fifteen".