77728019 has 2 divisors, whose sum is σ = 77728020. Its totient is φ = 77728018.

The previous prime is 77727997. The next prime is 77728073. The reversal of 77728019 is 91082777.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 77728019 - 2⁸ = 77727763 is a prime.

It is a super-2 number, since 2×77728019² = 12083289875328722, which contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (77728319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38864009 + 38864010.

It is an arithmetic number, because the mean of its divisors is an integer number (38864010).

Almost surely, 2^77728019 is an apocalyptic number.

77728019 is a deficient number, since it is larger than the sum of its proper divisors (1).

77728019 is an equidigital number, since it uses as much as digits as its factorization.

77728019 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 49392, while the sum is 41.

The square root of 77728019 is about 8816.3495280076. The cubic root of 77728019 is about 426.7686735949.

The spelling of 77728019 in words is "seventy-seven million, seven hundred twenty-eight thousand, nineteen".