77388991 has 4 divisors (see below), whose sum is σ = 77414184. Its totient is φ = 77363800.

The previous prime is 77388973. The next prime is 77389001. The reversal of 77388991 is 19988377.

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

It is a cyclic number.

It is not a de Polignac number, because 77388991 - 2⁵ = 77388959 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77388191) 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 in 3 ways as a sum of consecutive naturals, for example, 7225 + ... + 14386.

It is an arithmetic number, because the mean of its divisors is an integer number (19353546).

Almost surely, 2^77388991 is an apocalyptic number.

77388991 is a deficient number, since it is larger than the sum of its proper divisors (25193).

77388991 is a wasteful number, since it uses less digits than its factorization.

77388991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25192.

The product of its digits is 762048, while the sum is 52.

The square root of 77388991 is about 8797.1012839458. The cubic root of 77388991 is about 426.1472871941.

The spelling of 77388991 in words is "seventy-seven million, three hundred eighty-eight thousand, nine hundred ninety-one".