77390909 has 2 divisors, whose sum is σ = 77390910. Its totient is φ = 77390908.

The previous prime is 77390899. The next prime is 77390921. The reversal of 77390909 is 90909377.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45185284 + 32205625 = 6722^2 + 5675^2 .

It is a cyclic number.

It is not a de Polignac number, because 77390909 - 2⁴ = 77390893 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 77390909.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77390959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38695454 + 38695455.

It is an arithmetic number, because the mean of its divisors is an integer number (38695455).

Almost surely, 2^77390909 is an apocalyptic number.

It is an amenable number.

77390909 is a deficient number, since it is larger than the sum of its proper divisors (1).

77390909 is an equidigital number, since it uses as much as digits as its factorization.

77390909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 107163, while the sum is 44.

The square root of 77390909 is about 8797.2102964519. The cubic root of 77390909 is about 426.1508076937.

The spelling of 77390909 in words is "seventy-seven million, three hundred ninety thousand, nine hundred nine".