77919971 has 2 divisors, whose sum is σ = 77919972. Its totient is φ = 77919970.

The previous prime is 77919949. The next prime is 77919973. The reversal of 77919971 is 17991977.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 77919971 - 2²⁶ = 10811107 is a prime.

Together with 77919973, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (77919973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38959985 + 38959986.

It is an arithmetic number, because the mean of its divisors is an integer number (38959986).

Almost surely, 2^77919971 is an apocalyptic number.

77919971 is a deficient number, since it is larger than the sum of its proper divisors (1).

77919971 is an equidigital number, since it uses as much as digits as its factorization.

77919971 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 250047, while the sum is 50.

The square root of 77919971 is about 8827.2289536411. The cubic root of 77919971 is about 427.1196914125.

The spelling of 77919971 in words is "seventy-seven million, nine hundred nineteen thousand, nine hundred seventy-one".