78347939 has 4 divisors (see below), whose sum is σ = 79826256. Its totient is φ = 76869624.

The previous prime is 78347923. The next prime is 78347953. The reversal of 78347939 is 93974387.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 78347939 - 2⁴ = 78347923 is a prime.

It is a super-2 number, since 2×78347939² = 12276799091095442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78347909) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 739079 + ... + 739184.

It is an arithmetic number, because the mean of its divisors is an integer number (19956564).

Almost surely, 2^78347939 is an apocalyptic number.

78347939 is a deficient number, since it is larger than the sum of its proper divisors (1478317).

78347939 is a wasteful number, since it uses less digits than its factorization.

78347939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1478316.

The product of its digits is 1143072, while the sum is 50.

The square root of 78347939 is about 8851.4371149548. The cubic root of 78347939 is about 427.9002355035.

The spelling of 78347939 in words is "seventy-eight million, three hundred forty-seven thousand, nine hundred thirty-nine".