78397389 has 40 divisors (see below), whose sum is σ = 134629440. Its totient is φ = 44719776.

The previous prime is 78397379. The next prime is 78397399. The reversal of 78397389 is 98379387.

It is an interprime number because it is at equal distance from previous prime (78397379) and next prime (78397399).

It is not a de Polignac number, because 78397389 - 2⁴ = 78397373 is a prime.

It is a super-2 number, since 2×78397389² = 12292301204034642, which contains 22 as substring.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78397379) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 137497 + ... + 138065.

It is an arithmetic number, because the mean of its divisors is an integer number (3365736).

Almost surely, 2^78397389 is an apocalyptic number.

It is an amenable number.

78397389 is a deficient number, since it is larger than the sum of its proper divisors (56232051).

78397389 is an frugal number, since it uses more digits than its factorization.

78397389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 603 (or 579 counting only the distinct ones).

The product of its digits is 2286144, while the sum is 54.

The square root of 78397389 is about 8854.2300060480. The cubic root of 78397389 is about 427.9902409194.

The spelling of 78397389 in words is "seventy-eight million, three hundred ninety-seven thousand, three hundred eighty-nine".