78131321 has 4 divisors (see below), whose sum is σ = 78181200. Its totient is φ = 78081444.

The previous prime is 78131267. The next prime is 78131323. The reversal of 78131321 is 12313187.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 78131321 - 2⁶ = 78131257 is a prime.

It is a super-2 number, since 2×78131321² = 12209006642410082, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78131323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22511 + ... + 25748.

It is an arithmetic number, because the mean of its divisors is an integer number (19545300).

Almost surely, 2^78131321 is an apocalyptic number.

It is an amenable number.

78131321 is a deficient number, since it is larger than the sum of its proper divisors (49879).

78131321 is a wasteful number, since it uses less digits than its factorization.

78131321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49878.

The product of its digits is 1008, while the sum is 26.

The square root of 78131321 is about 8839.1923273566. The cubic root of 78131321 is about 427.5055157001.

The spelling of 78131321 in words is "seventy-eight million, one hundred thirty-one thousand, three hundred twenty-one".