78867391 has 4 divisors (see below), whose sum is σ = 82296432. Its totient is φ = 75438352.

The previous prime is 78867377. The next prime is 78867431. The reversal of 78867391 is 19376887.

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 78867391 - 2⁷ = 78867263 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78867331) 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, 1714486 + ... + 1714531.

It is an arithmetic number, because the mean of its divisors is an integer number (20574108).

Almost surely, 2^78867391 is an apocalyptic number.

78867391 is a deficient number, since it is larger than the sum of its proper divisors (3429041).

78867391 is a wasteful number, since it uses less digits than its factorization.

78867391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3429040.

The product of its digits is 508032, while the sum is 49.

The square root of 78867391 is about 8880.7314451007. The cubic root of 78867391 is about 428.8438221409.

The spelling of 78867391 in words is "seventy-eight million, eight hundred sixty-seven thousand, three hundred ninety-one".