7813180721 has 2 divisors, whose sum is σ = 7813180722. Its totient is φ = 7813180720.

The previous prime is 7813180699. The next prime is 7813180723. The reversal of 7813180721 is 1270813187.

7813180721 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4363263025 + 3449917696 = 66055^2 + 58736^2 .

It is a cyclic number.

It is not a de Polignac number, because 7813180721 - 2¹⁸ = 7812918577 is a prime.

It is a super-2 number, since 2×7813180721² (a number of 21 digits) contains 22 as substring.

Together with 7813180723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (7813180723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3906590360 + 3906590361.

It is an arithmetic number, because the mean of its divisors is an integer number (3906590361).

Almost surely, 2^7813180721 is an apocalyptic number.

It is an amenable number.

7813180721 is a deficient number, since it is larger than the sum of its proper divisors (1).

7813180721 is an equidigital number, since it uses as much as digits as its factorization.

7813180721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18816, while the sum is 38.

The square root of 7813180721 is about 88392.1983039227. The cubic root of 7813180721 is about 1984.3089440722.

The spelling of 7813180721 in words is "seven billion, eight hundred thirteen million, one hundred eighty thousand, seven hundred twenty-one".