78994891 has 2 divisors, whose sum is σ = 78994892. Its totient is φ = 78994890.

The previous prime is 78994879. The next prime is 78994967. The reversal of 78994891 is 19849987.

It is a weak prime.

It is an emirp because it is prime and its reverse (19849987) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78994891 - 2⁵ = 78994859 is a prime.

It is a Chen prime.

It is a plaindrome in base 12.

It is not a weakly prime, because it can be changed into another prime (78994831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39497445 + 39497446.

It is an arithmetic number, because the mean of its divisors is an integer number (39497446).

Almost surely, 2^78994891 is an apocalyptic number.

78994891 is a deficient number, since it is larger than the sum of its proper divisors (1).

78994891 is an equidigital number, since it uses as much as digits as its factorization.

78994891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1306368, while the sum is 55.

The square root of 78994891 is about 8887.9070089645. The cubic root of 78994891 is about 429.0747927548.

The spelling of 78994891 in words is "seventy-eight million, nine hundred ninety-four thousand, eight hundred ninety-one".