78684769 has 2 divisors, whose sum is σ = 78684770. Its totient is φ = 78684768.

The previous prime is 78684761. The next prime is 78684773. The reversal of 78684769 is 96748687.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50594769 + 28090000 = 7113^2 + 5300^2 .

It is a cyclic number.

It is not a de Polignac number, because 78684769 - 2³ = 78684761 is a prime.

It is a super-2 number, since 2×78684769² = 12382585745166722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78684761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39342384 + 39342385.

It is an arithmetic number, because the mean of its divisors is an integer number (39342385).

Almost surely, 2^78684769 is an apocalyptic number.

It is an amenable number.

78684769 is a deficient number, since it is larger than the sum of its proper divisors (1).

78684769 is an equidigital number, since it uses as much as digits as its factorization.

78684769 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4064256, while the sum is 55.

The square root of 78684769 is about 8870.4435627538. The cubic root of 78684769 is about 428.5125621105.

The spelling of 78684769 in words is "seventy-eight million, six hundred eighty-four thousand, seven hundred sixty-nine".