77280491 has 2 divisors, whose sum is σ = 77280492. Its totient is φ = 77280490.

The previous prime is 77280433. The next prime is 77280493. The reversal of 77280491 is 19408277.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77280491 is a prime.

It is a Sophie Germain prime.

Together with 77280493, 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 (77280493) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38640245 + 38640246.

It is an arithmetic number, because the mean of its divisors is an integer number (38640246).

Almost surely, 2^77280491 is an apocalyptic number.

77280491 is a deficient number, since it is larger than the sum of its proper divisors (1).

77280491 is an equidigital number, since it uses as much as digits as its factorization.

77280491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28224, while the sum is 38.

The square root of 77280491 is about 8790.9323168820. The cubic root of 77280491 is about 425.9480400526.

The spelling of 77280491 in words is "seventy-seven million, two hundred eighty thousand, four hundred ninety-one".