77971139 has 2 divisors, whose sum is σ = 77971140. Its totient is φ = 77971138.

The previous prime is 77971133. The next prime is 77971177. The reversal of 77971139 is 93117977.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (93117977) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77971139 - 2⁴ = 77971123 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 77971139.

It is not a weakly prime, because it can be changed into another prime (77971133) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38985569 + 38985570.

It is an arithmetic number, because the mean of its divisors is an integer number (38985570).

Almost surely, 2^77971139 is an apocalyptic number.

77971139 is a deficient number, since it is larger than the sum of its proper divisors (1).

77971139 is an equidigital number, since it uses as much as digits as its factorization.

77971139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 83349, while the sum is 44.

The square root of 77971139 is about 8830.1267827818. The cubic root of 77971139 is about 427.2131637192.

The spelling of 77971139 in words is "seventy-seven million, nine hundred seventy-one thousand, one hundred thirty-nine".