78288391 has 8 divisors (see below), whose sum is σ = 79120800. Its totient is φ = 77460768.

The previous prime is 78288373. The next prime is 78288407. The reversal of 78288391 is 19388287.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 78288391 - 2⁵ = 78288359 is a prime.

It is a super-2 number, since 2×78288391² = 12258144330737762, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78288191) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38205 + ... + 40201.

It is an arithmetic number, because the mean of its divisors is an integer number (9890100).

Almost surely, 2^78288391 is an apocalyptic number.

78288391 is a deficient number, since it is larger than the sum of its proper divisors (832409).

78288391 is a wasteful number, since it uses less digits than its factorization.

78288391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2393.

The product of its digits is 193536, while the sum is 46.

The square root of 78288391 is about 8848.0727280013. The cubic root of 78288391 is about 427.7918001413.

The spelling of 78288391 in words is "seventy-eight million, two hundred eighty-eight thousand, three hundred ninety-one".