61686890934637 has 2 divisors, whose sum is σ = 61686890934638. Its totient is φ = 61686890934636.

The previous prime is 61686890934521. The next prime is 61686890934659. The reversal of 61686890934637 is 73643909868616.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 36106470605956 + 25580420328681 = 6008866^2 + 5057709^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61686890934637 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61686890934667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30843445467318 + 30843445467319.

It is an arithmetic number, because the mean of its divisors is an integer number (30843445467319).

Almost surely, 2^{61686890934637} is an apocalyptic number.

It is an amenable number.

61686890934637 is a deficient number, since it is larger than the sum of its proper divisors (1).

61686890934637 is an equidigital number, since it uses as much as digits as its factorization.

61686890934637 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1693052928, while the sum is 76.

The spelling of 61686890934637 in words is "sixty-one trillion, six hundred eighty-six billion, eight hundred ninety million, nine hundred thirty-four thousand, six hundred thirty-seven".