78426331 has 2 divisors, whose sum is σ = 78426332. Its totient is φ = 78426330.

The previous prime is 78426329. The next prime is 78426371. The reversal of 78426331 is 13362487.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 78426331 - 2¹ = 78426329 is a prime.

It is a super-2 number, since 2×78426331² = 12301378788243122, which contains 22 as substring.

Together with 78426329, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (78426301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39213165 + 39213166.

It is an arithmetic number, because the mean of its divisors is an integer number (39213166).

Almost surely, 2^78426331 is an apocalyptic number.

78426331 is a deficient number, since it is larger than the sum of its proper divisors (1).

78426331 is an equidigital number, since it uses as much as digits as its factorization.

78426331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24192, while the sum is 34.

The square root of 78426331 is about 8855.8642153095. The cubic root of 78426331 is about 428.0429015574.

It can be divided in two parts, 78 and 426331, that added together give a square (426409 = 653²).

The spelling of 78426331 in words is "seventy-eight million, four hundred twenty-six thousand, three hundred thirty-one".