78698989 has 2 divisors, whose sum is σ = 78698990. Its totient is φ = 78698988.

The previous prime is 78698947. The next prime is 78698993. The reversal of 78698989 is 98989687.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 60062500 + 18636489 = 7750^2 + 4317^2 .

It is an emirp because it is prime and its reverse (98989687) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78698989 - 2¹⁷ = 78567917 is a prime.

It is a super-3 number, since 3×78698989³ (a number of 25 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 78698989.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78698929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39349494 + 39349495.

It is an arithmetic number, because the mean of its divisors is an integer number (39349495).

Almost surely, 2^78698989 is an apocalyptic number.

It is an amenable number.

78698989 is a deficient number, since it is larger than the sum of its proper divisors (1).

78698989 is an equidigital number, since it uses as much as digits as its factorization.

78698989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15676416, while the sum is 64.

The square root of 78698989 is about 8871.2450648147. The cubic root of 78698989 is about 428.5383743131.

The spelling of 78698989 in words is "seventy-eight million, six hundred ninety-eight thousand, nine hundred eighty-nine".