7215640681 has 2 divisors, whose sum is σ = 7215640682. Its totient is φ = 7215640680.

The previous prime is 7215640673. The next prime is 7215640709. The reversal of 7215640681 is 1860465127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5476000000 + 1739640681 = 74000^2 + 41709^2 .

It is a cyclic number.

It is not a de Polignac number, because 7215640681 - 2³ = 7215640673 is a prime.

It is a super-2 number, since 2×7215640681² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (7215640381) 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 as a sum of consecutive naturals, namely, 3607820340 + 3607820341.

It is an arithmetic number, because the mean of its divisors is an integer number (3607820341).

Almost surely, 2^7215640681 is an apocalyptic number.

It is an amenable number.

7215640681 is a deficient number, since it is larger than the sum of its proper divisors (1).

7215640681 is an equidigital number, since it uses as much as digits as its factorization.

7215640681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 80640, while the sum is 40.

The square root of 7215640681 is about 84944.9273411897. The cubic root of 7215640681 is about 1932.3759905072.

The spelling of 7215640681 in words is "seven billion, two hundred fifteen million, six hundred forty thousand, six hundred eighty-one".