51561515 has 16 divisors (see below), whose sum is σ = 66071808. Its totient is φ = 38534496.

The previous prime is 51561511. The next prime is 51561529. The reversal of 51561515 is 51516515.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 51561515 - 2² = 51561511 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51561511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 269 + ... + 10158.

It is an arithmetic number, because the mean of its divisors is an integer number (4129488).

Almost surely, 2^51561515 is an apocalyptic number.

51561515 is a deficient number, since it is larger than the sum of its proper divisors (14510293).

51561515 is a wasteful number, since it uses less digits than its factorization.

51561515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10498.

The product of its digits is 3750, while the sum is 29.

The square root of 51561515 is about 7180.6347212485. The cubic root of 51561515 is about 372.1990181652.

The spelling of 51561515 in words is "fifty-one million, five hundred sixty-one thousand, five hundred fifteen".