51515915 has 16 divisors (see below), whose sum is σ = 67896576. Its totient is φ = 37212000.

The previous prime is 51515869. The next prime is 51515923. The reversal of 51515915 is 51951515.

It is not a de Polignac number, because 51515915 - 2⁶ = 51515851 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5204 + ... + 11406.

It is an arithmetic number, because the mean of its divisors is an integer number (4243536).

Almost surely, 2^51515915 is an apocalyptic number.

51515915 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

51515915 is a deficient number, since it is larger than the sum of its proper divisors (16380661).

51515915 is a wasteful number, since it uses less digits than its factorization.

51515915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6370.

The product of its digits is 5625, while the sum is 32.

The square root of 51515915 is about 7177.4588121424. The cubic root of 51515915 is about 372.0892639490.

Subtracting 51515915 from its reverse (51951515), we obtain a square (435600 = 660²).

The spelling of 51515915 in words is "fifty-one million, five hundred fifteen thousand, nine hundred fifteen".