51115915 has 4 divisors (see below), whose sum is σ = 61339104. Its totient is φ = 40892728.

The previous prime is 51115879. The next prime is 51115927. The reversal of 51115915 is 51951115.

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 51115915 - 2²¹ = 49018763 is a prime.

It is a super-2 number, since 2×51115915² = 5225673532574450, which contains 22 as substring.

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, 5111587 + ... + 5111596.

It is an arithmetic number, because the mean of its divisors is an integer number (15334776).

Almost surely, 2^51115915 is an apocalyptic number.

51115915 is a deficient number, since it is larger than the sum of its proper divisors (10223189).

51115915 is a wasteful number, since it uses less digits than its factorization.

51115915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10223188.

The product of its digits is 1125, while the sum is 28.

The square root of 51115915 is about 7149.5394956598. The cubic root of 51115915 is about 371.1237203104.

It can be divided in two parts, 5111 and 5915, that added together give a triangular number (11026 = T₁₄₈).

The spelling of 51115915 in words is "fifty-one million, one hundred fifteen thousand, nine hundred fifteen".