51561616 has 20 divisors (see below), whose sum is σ = 101025900. Its totient is φ = 25490432.

The previous prime is 51561613. The next prime is 51561617. The reversal of 51561616 is 61616515.

It can be written as a sum of positive squares in 2 ways, for example, as 9363600 + 42198016 = 3060^2 + 6496^2 .

It is not an unprimeable number, because it can be changed into a prime (51561613) 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, 16681 + ... + 19528.

It is an arithmetic number, because the mean of its divisors is an integer number (5051295).

Almost surely, 2^51561616 is an apocalyptic number.

It is an amenable number.

51561616 is a deficient number, since it is larger than the sum of its proper divisors (49464284).

51561616 is a wasteful number, since it uses less digits than its factorization.

51561616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36306 (or 36300 counting only the distinct ones).

The product of its digits is 5400, while the sum is 31.

The square root of 51561616 is about 7180.6417540496. The cubic root of 51561616 is about 372.1992611894.

The spelling of 51561616 in words is "fifty-one million, five hundred sixty-one thousand, six hundred sixteen".