7991213 has 4 divisors (see below), whose sum is σ = 8011740. Its totient is φ = 7970688.

The previous prime is 7991209. The next prime is 7991219. The reversal of 7991213 is 3121997.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6360484 + 1630729 = 2522^2 + 1277^2 .

It is a cyclic number.

It is not a de Polignac number, because 7991213 - 2² = 7991209 is a prime.

It is a super-2 number, since 2×7991213² = 127718970422738, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 7991213.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7991219) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9668 + ... + 10461.

It is an arithmetic number, because the mean of its divisors is an integer number (2002935).

Almost surely, 2^7991213 is an apocalyptic number.

It is an amenable number.

7991213 is a deficient number, since it is larger than the sum of its proper divisors (20527).

7991213 is a wasteful number, since it uses less digits than its factorization.

7991213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20526.

The product of its digits is 3402, while the sum is 32.

The square root of 7991213 is about 2826.8733611536. The cubic root of 7991213 is about 199.9267481741.

The spelling of 7991213 in words is "seven million, nine hundred ninety-one thousand, two hundred thirteen".