51015515 has 4 divisors (see below), whose sum is σ = 61218624. Its totient is φ = 40812408.

The previous prime is 51015511. The next prime is 51015529. The reversal of 51015515 is 51551015.

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: 51551015 = 5 ⋅10310203.

It is a cyclic number.

It is not a de Polignac number, because 51015515 - 2² = 51015511 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51015511) 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, 5101547 + ... + 5101556.

It is an arithmetic number, because the mean of its divisors is an integer number (15304656).

Almost surely, 2^51015515 is an apocalyptic number.

51015515 is a deficient number, since it is larger than the sum of its proper divisors (10203109).

51015515 is a wasteful number, since it uses less digits than its factorization.

51015515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10203108.

The product of its (nonzero) digits is 625, while the sum is 23.

The square root of 51015515 is about 7142.5146132157. The cubic root of 51015515 is about 370.8805785308.

The spelling of 51015515 in words is "fifty-one million, fifteen thousand, five hundred fifteen".