77728291 has 2 divisors, whose sum is σ = 77728292. Its totient is φ = 77728290.

The previous prime is 77728289. The next prime is 77728309. The reversal of 77728291 is 19282777.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 77728291 - 2¹ = 77728289 is a prime.

Together with 77728289, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (77728591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38864145 + 38864146.

It is an arithmetic number, because the mean of its divisors is an integer number (38864146).

Almost surely, 2^77728291 is an apocalyptic number.

77728291 is a deficient number, since it is larger than the sum of its proper divisors (1).

77728291 is an equidigital number, since it uses as much as digits as its factorization.

77728291 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 98784, while the sum is 43.

The square root of 77728291 is about 8816.3649538798. The cubic root of 77728291 is about 426.7691714031.

The spelling of 77728291 in words is "seventy-seven million, seven hundred twenty-eight thousand, two hundred ninety-one".