78398739 has 8 divisors (see below), whose sum is σ = 116146320. Its totient is φ = 52265808.

The previous prime is 78398737. The next prime is 78398741. The reversal of 78398739 is 93789387.

It is an interprime number because it is at equal distance from previous prime (78398737) and next prime (78398741).

It is not a de Polignac number, because 78398739 - 2¹ = 78398737 is a prime.

It is a super-2 number, since 2×78398739² = 12292724553580242, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78398737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1451802 + ... + 1451855.

It is an arithmetic number, because the mean of its divisors is an integer number (14518290).

Almost surely, 2^78398739 is an apocalyptic number.

78398739 is a deficient number, since it is larger than the sum of its proper divisors (37747581).

78398739 is a wasteful number, since it uses less digits than its factorization.

78398739 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2903666 (or 2903660 counting only the distinct ones).

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

The square root of 78398739 is about 8854.3062404685. The cubic root of 78398739 is about 427.9926975637.

The spelling of 78398739 in words is "seventy-eight million, three hundred ninety-eight thousand, seven hundred thirty-nine".