51215315 has 4 divisors (see below), whose sum is σ = 61458384. Its totient is φ = 40972248.

The previous prime is 51215309. The next prime is 51215347. The reversal of 51215315 is 51351215.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 51351215 = 5 ⋅10270243.

It is a cyclic number.

It is not a de Polignac number, because 51215315 - 2²² = 47021011 is a prime.

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, 5121527 + ... + 5121536.

It is an arithmetic number, because the mean of its divisors is an integer number (15364596).

Almost surely, 2^51215315 is an apocalyptic number.

51215315 is a deficient number, since it is larger than the sum of its proper divisors (10243069).

51215315 is a wasteful number, since it uses less digits than its factorization.

51215315 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10243068.

The product of its digits is 750, while the sum is 23.

The square root of 51215315 is about 7156.4876161424. The cubic root of 51215315 is about 371.3641269215.

The spelling of 51215315 in words is "fifty-one million, two hundred fifteen thousand, three hundred fifteen".