77665897 has 2 divisors, whose sum is σ = 77665898. Its totient is φ = 77665896.

The previous prime is 77665891. The next prime is 77665909. The reversal of 77665897 is 79856677.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 52475536 + 25190361 = 7244^2 + 5019^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77665897 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (77665891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38832948 + 38832949.

It is an arithmetic number, because the mean of its divisors is an integer number (38832949).

Almost surely, 2^77665897 is an apocalyptic number.

It is an amenable number.

77665897 is a deficient number, since it is larger than the sum of its proper divisors (1).

77665897 is an equidigital number, since it uses as much as digits as its factorization.

77665897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4445280, while the sum is 55.

The square root of 77665897 is about 8812.8257102929. The cubic root of 77665897 is about 426.6549488834.

The spelling of 77665897 in words is "seventy-seven million, six hundred sixty-five thousand, eight hundred ninety-seven".