77943689 has 2 divisors, whose sum is σ = 77943690. Its totient is φ = 77943688.

The previous prime is 77943673. The next prime is 77943709. The reversal of 77943689 is 98634977.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 74995600 + 2948089 = 8660^2 + 1717^2 .

It is a cyclic number.

It is not a de Polignac number, because 77943689 - 2⁴ = 77943673 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 77943689.

It is not a weakly prime, because it can be changed into another prime (77943659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38971844 + 38971845.

It is an arithmetic number, because the mean of its divisors is an integer number (38971845).

Almost surely, 2^77943689 is an apocalyptic number.

It is an amenable number.

77943689 is a deficient number, since it is larger than the sum of its proper divisors (1).

77943689 is an equidigital number, since it uses as much as digits as its factorization.

77943689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2286144, while the sum is 53.

The square root of 77943689 is about 8828.5723081368. The cubic root of 77943689 is about 427.1630238942.

The spelling of 77943689 in words is "seventy-seven million, nine hundred forty-three thousand, six hundred eighty-nine".