51582687661 has 2 divisors, whose sum is σ = 51582687662. Its totient is φ = 51582687660.

The previous prime is 51582687659. The next prime is 51582687731. The reversal of 51582687661 is 16678628515.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50937781636 + 644906025 = 225694^2 + 25395^2 .

It is a cyclic number.

It is not a de Polignac number, because 51582687661 - 2¹ = 51582687659 is a prime.

Together with 51582687659, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51582682661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25791343830 + 25791343831.

It is an arithmetic number, because the mean of its divisors is an integer number (25791343831).

Almost surely, 2^51582687661 is an apocalyptic number.

It is an amenable number.

51582687661 is a deficient number, since it is larger than the sum of its proper divisors (1).

51582687661 is an equidigital number, since it uses as much as digits as its factorization.

51582687661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4838400, while the sum is 55.

The spelling of 51582687661 in words is "fifty-one billion, five hundred eighty-two million, six hundred eighty-seven thousand, six hundred sixty-one".