78642331 has 2 divisors, whose sum is σ = 78642332. Its totient is φ = 78642330.

The previous prime is 78642329. The next prime is 78642371. The reversal of 78642331 is 13324687.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (13324687) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78642331 - 2¹ = 78642329 is a prime.

It is a super-2 number, since 2×78642331² = 12369232450227122, which contains 22 as substring.

Together with 78642329, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (78642371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39321165 + 39321166.

It is an arithmetic number, because the mean of its divisors is an integer number (39321166).

Almost surely, 2^78642331 is an apocalyptic number.

78642331 is a deficient number, since it is larger than the sum of its proper divisors (1).

78642331 is an equidigital number, since it uses as much as digits as its factorization.

78642331 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 78642331 is about 8868.0511387790. The cubic root of 78642331 is about 428.4355099835.

The spelling of 78642331 in words is "seventy-eight million, six hundred forty-two thousand, three hundred thirty-one".