666113621 has 2 divisors, whose sum is σ = 666113622. Its totient is φ = 666113620.

The previous prime is 666113579. The next prime is 666113633. The reversal of 666113621 is 126311666.

666113621 is digitally balanced in base 2, 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., 370755025 + 295358596 = 19255^2 + 17186^2 .

It is a cyclic number.

It is not a de Polignac number, because 666113621 - 2¹⁰ = 666112597 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666113521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333056810 + 333056811.

It is an arithmetic number, because the mean of its divisors is an integer number (333056811).

Almost surely, 2^666113621 is an apocalyptic number.

It is an amenable number.

666113621 is a deficient number, since it is larger than the sum of its proper divisors (1).

666113621 is an equidigital number, since it uses as much as digits as its factorization.

666113621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7776, while the sum is 32.

The square root of 666113621 is about 25809.1770694069. The cubic root of 666113621 is about 873.3388329620.

The spelling of 666113621 in words is "six hundred sixty-six million, one hundred thirteen thousand, six hundred twenty-one".