51561637 has 2 divisors, whose sum is σ = 51561638. Its totient is φ = 51561636.

The previous prime is 51561617. The next prime is 51561673. The reversal of 51561637 is 73616515.

Together with next prime (51561673) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 39513796 + 12047841 = 6286^2 + 3471^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51561637 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51561617) 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 as a sum of consecutive naturals, namely, 25780818 + 25780819.

It is an arithmetic number, because the mean of its divisors is an integer number (25780819).

Almost surely, 2^51561637 is an apocalyptic number.

It is an amenable number.

51561637 is a deficient number, since it is larger than the sum of its proper divisors (1).

51561637 is an equidigital number, since it uses as much as digits as its factorization.

51561637 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18900, while the sum is 34.

The square root of 51561637 is about 7180.6432163143. The cubic root of 51561637 is about 372.1993117191.

The spelling of 51561637 in words is "fifty-one million, five hundred sixty-one thousand, six hundred thirty-seven".