77961613 has 2 divisors, whose sum is σ = 77961614. Its totient is φ = 77961612.

The previous prime is 77961607. The next prime is 77961629. The reversal of 77961613 is 31616977.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 72216004 + 5745609 = 8498^2 + 2397^2 .

It is a cyclic number.

It is not a de Polignac number, because 77961613 - 2⁵ = 77961581 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77961913) 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, 38980806 + 38980807.

It is an arithmetic number, because the mean of its divisors is an integer number (38980807).

Almost surely, 2^77961613 is an apocalyptic number.

It is an amenable number.

77961613 is a deficient number, since it is larger than the sum of its proper divisors (1).

77961613 is an equidigital number, since it uses as much as digits as its factorization.

77961613 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 47628, while the sum is 40.

The square root of 77961613 is about 8829.5873629519. The cubic root of 77961613 is about 427.1957649808.

It can be divided in two parts, 7796 and 1613, that added together give a square (9409 = 97²).

The spelling of 77961613 in words is "seventy-seven million, nine hundred sixty-one thousand, six hundred thirteen".