77661497929 has 2 divisors, whose sum is σ = 77661497930. Its totient is φ = 77661497928.

The previous prime is 77661497899. The next prime is 77661497983. The reversal of 77661497929 is 92979416677.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 72307210000 + 5354287929 = 268900^2 + 73173^2 .

It is a cyclic number.

It is not a de Polignac number, because 77661497929 - 2⁵ = 77661497897 is a prime.

It is not a weakly prime, because it can be changed into another prime (77661494929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38830748964 + 38830748965.

It is an arithmetic number, because the mean of its divisors is an integer number (38830748965).

Almost surely, 2^77661497929 is an apocalyptic number.

It is an amenable number.

77661497929 is a deficient number, since it is larger than the sum of its proper divisors (1).

77661497929 is an equidigital number, since it uses as much as digits as its factorization.

77661497929 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72013536, while the sum is 67.

The spelling of 77661497929 in words is "seventy-seven billion, six hundred sixty-one million, four hundred ninety-seven thousand, nine hundred twenty-nine".