77640055 has 4 divisors (see below), whose sum is σ = 93168072. Its totient is φ = 62112040.

The previous prime is 77640041. The next prime is 77640067. The reversal of 77640055 is 55004677.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 77640055 - 2⁹ = 77639543 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 77640055.

It is a congruent number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 7764001 + ... + 7764010.

It is an arithmetic number, because the mean of its divisors is an integer number (23292018).

Almost surely, 2^77640055 is an apocalyptic number.

77640055 is a deficient number, since it is larger than the sum of its proper divisors (15528017).

77640055 is a wasteful number, since it uses less digits than its factorization.

77640055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15528016.

The product of its (nonzero) digits is 29400, while the sum is 34.

The square root of 77640055 is about 8811.3594297361. The cubic root of 77640055 is about 426.6076229196.

The spelling of 77640055 in words is "seventy-seven million, six hundred forty thousand, fifty-five".