77890639 has 2 divisors, whose sum is σ = 77890640. Its totient is φ = 77890638.

The previous prime is 77890619. The next prime is 77890643. The reversal of 77890639 is 93609877.

It is a strong prime.

It is an emirp because it is prime and its reverse (93609877) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77890639 - 2⁷ = 77890511 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 77890592 and 77890601.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77890619) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38945319 + 38945320.

It is an arithmetic number, because the mean of its divisors is an integer number (38945320).

Almost surely, 2^77890639 is an apocalyptic number.

77890639 is a deficient number, since it is larger than the sum of its proper divisors (1).

77890639 is an equidigital number, since it uses as much as digits as its factorization.

77890639 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 571536, while the sum is 49.

The square root of 77890639 is about 8825.5673472021. The cubic root of 77890639 is about 427.0660900614.

The spelling of 77890639 in words is "seventy-seven million, eight hundred ninety thousand, six hundred thirty-nine".