78399375 has 20 divisors (see below), whose sum is σ = 130626936. Its totient is φ = 41812000.

The previous prime is 78399353. The next prime is 78399379. The reversal of 78399375 is 57399387.

It is a happy number.

It is not a de Polignac number, because 78399375 - 2⁶ = 78399311 is a prime.

It is a super-2 number, since 2×78399375² = 12292924000781250, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78399379) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 19032 + ... + 22781.

Almost surely, 2^78399375 is an apocalyptic number.

78399375 is a gapful number since it is divisible by the number (75) formed by its first and last digit.

78399375 is a deficient number, since it is larger than the sum of its proper divisors (52227561).

78399375 is an equidigital number, since it uses as much as digits as its factorization.

78399375 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41836 (or 41821 counting only the distinct ones).

The product of its digits is 1428840, while the sum is 51.

The square root of 78399375 is about 8854.3421551237. The cubic root of 78399375 is about 427.9938549064.

The spelling of 78399375 in words is "seventy-eight million, three hundred ninety-nine thousand, three hundred seventy-five".