61686631 has 2 divisors, whose sum is σ = 61686632. Its totient is φ = 61686630.

The previous prime is 61686629. The next prime is 61686637. The reversal of 61686631 is 13668616.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 61686631 - 2¹ = 61686629 is a prime.

It is a super-2 number, since 2×61686631² = 7610480888260322, which contains 22 as substring.

Together with 61686629, 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 (61686637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30843315 + 30843316.

It is an arithmetic number, because the mean of its divisors is an integer number (30843316).

Almost surely, 2^61686631 is an apocalyptic number.

61686631 is a deficient number, since it is larger than the sum of its proper divisors (1).

61686631 is an equidigital number, since it uses as much as digits as its factorization.

61686631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 37.

The square root of 61686631 is about 7854.0837148582. The cubic root of 61686631 is about 395.1212168699.

The spelling of 61686631 in words is "sixty-one million, six hundred eighty-six thousand, six hundred thirty-one".