77921393 has 4 divisors (see below), whose sum is σ = 85005168. Its totient is φ = 70837620.

The previous prime is 77921357. The next prime is 77921407. The reversal of 77921393 is 39312977.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 77921393 - 2¹⁰ = 77920369 is a prime.

It is a Duffinian number.

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 77921393.

It is not an unprimeable number, because it can be changed into a prime (77921303) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3541871 + ... + 3541892.

It is an arithmetic number, because the mean of its divisors is an integer number (21251292).

Almost surely, 2^77921393 is an apocalyptic number.

It is an amenable number.

77921393 is a deficient number, since it is larger than the sum of its proper divisors (7083775).

77921393 is a wasteful number, since it uses less digits than its factorization.

77921393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7083774.

The product of its digits is 71442, while the sum is 41.

The square root of 77921393 is about 8827.3094995021. The cubic root of 77921393 is about 427.1222896360.

The spelling of 77921393 in words is "seventy-seven million, nine hundred twenty-one thousand, three hundred ninety-three".