78899813 has 2 divisors, whose sum is σ = 78899814. Its totient is φ = 78899812.

The previous prime is 78899809. The next prime is 78899831. The reversal of 78899813 is 31899887.

Together with next prime (78899831) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49815364 + 29084449 = 7058^2 + 5393^2 .

It is a cyclic number.

It is not a de Polignac number, because 78899813 - 2² = 78899809 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78899833) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39449906 + 39449907.

It is an arithmetic number, because the mean of its divisors is an integer number (39449907).

Almost surely, 2^78899813 is an apocalyptic number.

It is an amenable number.

78899813 is a deficient number, since it is larger than the sum of its proper divisors (1).

78899813 is an equidigital number, since it uses as much as digits as its factorization.

78899813 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 870912, while the sum is 53.

The square root of 78899813 is about 8882.5566702386. The cubic root of 78899813 is about 428.9025792917.

The spelling of 78899813 in words is "seventy-eight million, eight hundred ninety-nine thousand, eight hundred thirteen".