77664247 has 4 divisors (see below), whose sum is σ = 78032536. Its totient is φ = 77295960.

The previous prime is 77664241. The next prime is 77664263. The reversal of 77664247 is 74246677.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 77664247 - 2¹⁵ = 77631479 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77664241) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 183828 + ... + 184249.

It is an arithmetic number, because the mean of its divisors is an integer number (19508134).

Almost surely, 2^77664247 is an apocalyptic number.

77664247 is a deficient number, since it is larger than the sum of its proper divisors (368289).

77664247 is a wasteful number, since it uses less digits than its factorization.

77664247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 368288.

The product of its digits is 395136, while the sum is 43.

The square root of 77664247 is about 8812.7320962344. The cubic root of 77664247 is about 426.6519274558.

The spelling of 77664247 in words is "seventy-seven million, six hundred sixty-four thousand, two hundred forty-seven".