7997581 has 2 divisors, whose sum is σ = 7997582. Its totient is φ = 7997580.

The previous prime is 7997579. The next prime is 7997621. The reversal of 7997581 is 1857997.

7997581 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4515625 + 3481956 = 2125^2 + 1866^2 .

It is a cyclic number.

It is not a de Polignac number, because 7997581 - 2¹ = 7997579 is a prime.

It is a super-2 number, since 2×7997581² = 127922603703122, which contains 22 as substring.

Together with 7997579, it forms a pair of twin primes.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7997551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3998790 + 3998791.

It is an arithmetic number, because the mean of its divisors is an integer number (3998791).

Almost surely, 2^7997581 is an apocalyptic number.

It is an amenable number.

7997581 is a deficient number, since it is larger than the sum of its proper divisors (1).

7997581 is an equidigital number, since it uses as much as digits as its factorization.

7997581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 158760, while the sum is 46.

The square root of 7997581 is about 2827.9994695898. Note that the first 3 decimals coincide. The cubic root of 7997581 is about 199.9798396345.

The spelling of 7997581 in words is "seven million, nine hundred ninety-seven thousand, five hundred eighty-one".