77920993 has 2 divisors, whose sum is σ = 77920994. Its totient is φ = 77920992.

The previous prime is 77920991. The next prime is 77921017. The reversal of 77920993 is 39902977.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42732369 + 35188624 = 6537^2 + 5932^2 .

It is an emirp because it is prime and its reverse (39902977) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77920993 - 2¹ = 77920991 is a prime.

Together with 77920991, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (77920991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38960496 + 38960497.

It is an arithmetic number, because the mean of its divisors is an integer number (38960497).

Almost surely, 2^77920993 is an apocalyptic number.

It is an amenable number.

77920993 is a deficient number, since it is larger than the sum of its proper divisors (1).

77920993 is an equidigital number, since it uses as much as digits as its factorization.

77920993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 214326, while the sum is 46.

The square root of 77920993 is about 8827.2868425128. The cubic root of 77920993 is about 427.1215587746.

The spelling of 77920993 in words is "seventy-seven million, nine hundred twenty thousand, nine hundred ninety-three".