77221379 has 2 divisors, whose sum is σ = 77221380. Its totient is φ = 77221378.

The previous prime is 77221369. The next prime is 77221381. The reversal of 77221379 is 97312277.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77221379 is a prime.

It is a Sophie Germain prime.

Together with 77221381, it forms a pair of twin primes.

It is a Chen prime.

It is a pancake number, because a pancake can be divided into 77221379 parts by 12427 straight cuts.

It is not a weakly prime, because it can be changed into another prime (77221349) 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, 38610689 + 38610690.

It is an arithmetic number, because the mean of its divisors is an integer number (38610690).

Almost surely, 2^77221379 is an apocalyptic number.

77221379 is a deficient number, since it is larger than the sum of its proper divisors (1).

77221379 is an equidigital number, since it uses as much as digits as its factorization.

77221379 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 37044, while the sum is 38.

The square root of 77221379 is about 8787.5695729821. The cubic root of 77221379 is about 425.8394095186.

The spelling of 77221379 in words is "seventy-seven million, two hundred twenty-one thousand, three hundred seventy-nine".