7212640021 has 2 divisors, whose sum is σ = 7212640022. Its totient is φ = 7212640020.

The previous prime is 7212640013. The next prime is 7212640033. The reversal of 7212640021 is 1200462127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5385504996 + 1827135025 = 73386^2 + 42745^2 .

It is a cyclic number.

It is not a de Polignac number, because 7212640021 - 2³ = 7212640013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7212643021) 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, 3606320010 + 3606320011.

It is an arithmetic number, because the mean of its divisors is an integer number (3606320011).

Almost surely, 2^7212640021 is an apocalyptic number.

It is an amenable number.

7212640021 is a deficient number, since it is larger than the sum of its proper divisors (1).

7212640021 is an equidigital number, since it uses as much as digits as its factorization.

7212640021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 7212640021 is about 84927.2631196838. The cubic root of 7212640021 is about 1932.1080906516.

The spelling of 7212640021 in words is "seven billion, two hundred twelve million, six hundred forty thousand, twenty-one".