78855913 has 2 divisors, whose sum is σ = 78855914. Its totient is φ = 78855912.

The previous prime is 78855883. The next prime is 78855929. The reversal of 78855913 is 31955887.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75481344 + 3374569 = 8688^2 + 1837^2 .

It is a cyclic number.

It is not a de Polignac number, because 78855913 - 2²¹ = 76758761 is a prime.

It is a super-4 number, since 4×78855913⁴ (a number of 33 digits) contains 4444 as substring.

It is not a weakly prime, because it can be changed into another prime (78855943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39427956 + 39427957.

It is an arithmetic number, because the mean of its divisors is an integer number (39427957).

Almost surely, 2^78855913 is an apocalyptic number.

It is an amenable number.

78855913 is a deficient number, since it is larger than the sum of its proper divisors (1).

78855913 is an equidigital number, since it uses as much as digits as its factorization.

78855913 is an evil number, because the sum of its binary digits is even.

The product of its digits is 302400, while the sum is 46.

The square root of 78855913 is about 8880.0851910328. The cubic root of 78855913 is about 428.8230171410.

The spelling of 78855913 in words is "seventy-eight million, eight hundred fifty-five thousand, nine hundred thirteen".