77894639 has 2 divisors, whose sum is σ = 77894640. Its totient is φ = 77894638.

The previous prime is 77894611. The next prime is 77894647. The reversal of 77894639 is 93649877.

It is a strong prime.

It is an emirp because it is prime and its reverse (93649877) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77894639 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77894689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38947319 + 38947320.

It is an arithmetic number, because the mean of its divisors is an integer number (38947320).

Almost surely, 2^77894639 is an apocalyptic number.

77894639 is a deficient number, since it is larger than the sum of its proper divisors (1).

77894639 is an equidigital number, since it uses as much as digits as its factorization.

77894639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2286144, while the sum is 53.

The square root of 77894639 is about 8825.7939586192. The cubic root of 77894639 is about 427.0734004612.

The spelling of 77894639 in words is "seventy-seven million, eight hundred ninety-four thousand, six hundred thirty-nine".