78709091 has 2 divisors, whose sum is σ = 78709092. Its totient is φ = 78709090.

The previous prime is 78709061. The next prime is 78709097. The reversal of 78709091 is 19090787.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78709091 is a prime.

It is not a weakly prime, because it can be changed into another prime (78709097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39354545 + 39354546.

It is an arithmetic number, because the mean of its divisors is an integer number (39354546).

Almost surely, 2^78709091 is an apocalyptic number.

78709091 is a deficient number, since it is larger than the sum of its proper divisors (1).

78709091 is an equidigital number, since it uses as much as digits as its factorization.

78709091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31752, while the sum is 41.

The square root of 78709091 is about 8871.8144141996. The cubic root of 78709091 is about 428.5567096162.

It can be divided in two parts, 7870 and 9091, that added together give a palindrome (16961).

The spelling of 78709091 in words is "seventy-eight million, seven hundred nine thousand, ninety-one".