61916581 has 2 divisors, whose sum is σ = 61916582. Its totient is φ = 61916580.

The previous prime is 61916551. The next prime is 61916587. The reversal of 61916581 is 18561916.

61916581 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 40525956 + 21390625 = 6366^2 + 4625^2 .

It is a cyclic number.

It is not a de Polignac number, because 61916581 - 2⁵ = 61916549 is a prime.

It is a super-2 number, since 2×61916581² = 7667326005459122, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 61916581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61916587) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30958290 + 30958291.

It is an arithmetic number, because the mean of its divisors is an integer number (30958291).

Almost surely, 2^61916581 is an apocalyptic number.

It is an amenable number.

61916581 is a deficient number, since it is larger than the sum of its proper divisors (1).

61916581 is an equidigital number, since it uses as much as digits as its factorization.

61916581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 37.

The square root of 61916581 is about 7868.7089792418. The cubic root of 61916581 is about 395.6115741155.

The spelling of 61916581 in words is "sixty-one million, nine hundred sixteen thousand, five hundred eighty-one".