77953991 has 2 divisors, whose sum is σ = 77953992. Its totient is φ = 77953990.

The previous prime is 77953957. The next prime is 77954003. The reversal of 77953991 is 19935977.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 77953991 - 2¹⁰ = 77952967 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77953951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38976995 + 38976996.

It is an arithmetic number, because the mean of its divisors is an integer number (38976996).

Almost surely, 2^77953991 is an apocalyptic number.

77953991 is a deficient number, since it is larger than the sum of its proper divisors (1).

77953991 is an equidigital number, since it uses as much as digits as its factorization.

77953991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 535815, while the sum is 50.

The square root of 77953991 is about 8829.1557354030. The cubic root of 77953991 is about 427.1818427777.

The spelling of 77953991 in words is "seventy-seven million, nine hundred fifty-three thousand, nine hundred ninety-one".