77979919 has 2 divisors, whose sum is σ = 77979920. Its totient is φ = 77979918.

The previous prime is 77979917. The next prime is 77979943. The reversal of 77979919 is 91997977.

It is a weak prime.

It is an emirp because it is prime and its reverse (91997977) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77979919 - 2¹ = 77979917 is a prime.

It is a super-2 number, since 2×77979919² = 12161735534493122, which contains 22 as substring.

Together with 77979917, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77979917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38989959 + 38989960.

It is an arithmetic number, because the mean of its divisors is an integer number (38989960).

Almost surely, 2^77979919 is an apocalyptic number.

77979919 is a deficient number, since it is larger than the sum of its proper divisors (1).

77979919 is an equidigital number, since it uses as much as digits as its factorization.

77979919 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2250423, while the sum is 58.

The square root of 77979919 is about 8830.6239303913. The cubic root of 77979919 is about 427.2291986728.

The spelling of 77979919 in words is "seventy-seven million, nine hundred seventy-nine thousand, nine hundred nineteen".