78857231 has 2 divisors, whose sum is σ = 78857232. Its totient is φ = 78857230.

The previous prime is 78857173. The next prime is 78857257. The reversal of 78857231 is 13275887.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78857231 - 2⁶ = 78857167 is a prime.

It is a super-2 number, since 2×78857231² = 12436925761974722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78857431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39428615 + 39428616.

It is an arithmetic number, because the mean of its divisors is an integer number (39428616).

Almost surely, 2^78857231 is an apocalyptic number.

78857231 is a deficient number, since it is larger than the sum of its proper divisors (1).

78857231 is an equidigital number, since it uses as much as digits as its factorization.

78857231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 94080, while the sum is 41.

The square root of 78857231 is about 8880.1594017225. The cubic root of 78857231 is about 428.8254062478.

The spelling of 78857231 in words is "seventy-eight million, eight hundred fifty-seven thousand, two hundred thirty-one".