78091213 has 2 divisors, whose sum is σ = 78091214. Its totient is φ = 78091212.

The previous prime is 78091199. The next prime is 78091219. The reversal of 78091213 is 31219087.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77211369 + 879844 = 8787^2 + 938^2 .

It is an emirp because it is prime and its reverse (31219087) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78091213 is a prime.

It is a super-2 number, since 2×78091213² = 12196475095622738, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78091219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39045606 + 39045607.

It is an arithmetic number, because the mean of its divisors is an integer number (39045607).

Almost surely, 2^78091213 is an apocalyptic number.

It is an amenable number.

78091213 is a deficient number, since it is larger than the sum of its proper divisors (1).

78091213 is an equidigital number, since it uses as much as digits as its factorization.

78091213 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 78091213 is about 8836.9232767972. The cubic root of 78091213 is about 427.4323511619.

The spelling of 78091213 in words is "seventy-eight million, ninety-one thousand, two hundred thirteen".