77661909 has 40 divisors (see below), whose sum is σ = 126114912. Its totient is φ = 47342880.

The previous prime is 77661901. The next prime is 77661919. The reversal of 77661909 is 90916677.

It is not a de Polignac number, because 77661909 - 2³ = 77661901 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77661901) 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 in 39 ways as a sum of consecutive naturals, for example, 137662 + ... + 138224.

Almost surely, 2^77661909 is an apocalyptic number.

It is an amenable number.

77661909 is a deficient number, since it is larger than the sum of its proper divisors (48453003).

77661909 is a wasteful number, since it uses less digits than its factorization.

77661909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 719 (or 710 counting only the distinct ones).

The product of its (nonzero) digits is 142884, while the sum is 45.

The square root of 77661909 is about 8812.5994462474. The cubic root of 77661909 is about 426.6476461112.

The spelling of 77661909 in words is "seventy-seven million, six hundred sixty-one thousand, nine hundred nine".