78312173 has 8 divisors (see below), whose sum is σ = 80382456. Its totient is φ = 76249600.

The previous prime is 78312139. The next prime is 78312187. The reversal of 78312173 is 37121387.

It can be written as a sum of positive squares in 4 ways, for example, as 7382089 + 70930084 = 2717^2 + 8422^2 .

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 78312173 - 2⁶ = 78312109 is a prime.

It is a super-2 number, since 2×78312173² = 12265592879963858, 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 (78312133) 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, 22703 + ... + 25923.

It is an arithmetic number, because the mean of its divisors is an integer number (10047807).

Almost surely, 2^78312173 is an apocalyptic number.

It is an amenable number.

78312173 is a deficient number, since it is larger than the sum of its proper divisors (2070283).

78312173 is a wasteful number, since it uses less digits than its factorization.

78312173 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3855.

The product of its digits is 7056, while the sum is 32.

The square root of 78312173 is about 8849.4165344389. The cubic root of 78312173 is about 427.8351131385.

The spelling of 78312173 in words is "seventy-eight million, three hundred twelve thousand, one hundred seventy-three".