77921111 has 2 divisors, whose sum is σ = 77921112. Its totient is φ = 77921110.

The previous prime is 77921099. The next prime is 77921113. The reversal of 77921111 is 11112977.

It is a strong prime.

It is an emirp because it is prime and its reverse (11112977) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77921111 is a prime.

It is a Sophie Germain prime.

Together with 77921113, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77921113) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38960555 + 38960556.

It is an arithmetic number, because the mean of its divisors is an integer number (38960556).

Almost surely, 2^77921111 is an apocalyptic number.

77921111 is a deficient number, since it is larger than the sum of its proper divisors (1).

77921111 is an equidigital number, since it uses as much as digits as its factorization.

77921111 is an evil number, because the sum of its binary digits is even.

The product of its digits is 882, while the sum is 29.

The square root of 77921111 is about 8827.2935263307. The cubic root of 77921111 is about 427.1217743790.

The spelling of 77921111 in words is "seventy-seven million, nine hundred twenty-one thousand, one hundred eleven".