7990813 has 2 divisors, whose sum is σ = 7990814. Its totient is φ = 7990812.

The previous prime is 7990789. The next prime is 7990823. The reversal of 7990813 is 3180997.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7717284 + 273529 = 2778^2 + 523^2 .

It is an emirp because it is prime and its reverse (3180997) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7990813 - 2²¹ = 5893661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7990823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3995406 + 3995407.

It is an arithmetic number, because the mean of its divisors is an integer number (3995407).

Almost surely, 2^7990813 is an apocalyptic number.

It is an amenable number.

7990813 is a deficient number, since it is larger than the sum of its proper divisors (1).

7990813 is an equidigital number, since it uses as much as digits as its factorization.

7990813 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13608, while the sum is 37.

The square root of 7990813 is about 2826.8026107247. The cubic root of 7990813 is about 199.9234123421.

The spelling of 7990813 in words is "seven million, nine hundred ninety thousand, eight hundred thirteen".