641402009 has 2 divisors, whose sum is σ = 641402010. Its totient is φ = 641402008.

The previous prime is 641401973. The next prime is 641402023. The reversal of 641402009 is 900204146.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 599515225 + 41886784 = 24485^2 + 6472^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-641402009 is a prime.

It is a super-2 number, since 2×641402009² = 822793074298472162, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (641402029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320701004 + 320701005.

It is an arithmetic number, because the mean of its divisors is an integer number (320701005).

Almost surely, 2^641402009 is an apocalyptic number.

It is an amenable number.

641402009 is a deficient number, since it is larger than the sum of its proper divisors (1).

641402009 is an equidigital number, since it uses as much as digits as its factorization.

641402009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 641402009 is about 25325.9157583689. The cubic root of 641402009 is about 862.4026955691.

The spelling of 641402009 in words is "six hundred forty-one million, four hundred two thousand, nine".