640100161 has 2 divisors, whose sum is σ = 640100162. Its totient is φ = 640100160.

The previous prime is 640100141. The next prime is 640100179. The reversal of 640100161 is 161001046.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 409819536 + 230280625 = 20244^2 + 15175^2 .

It is a cyclic number.

It is not a de Polignac number, because 640100161 - 2¹⁹ = 639575873 is a prime.

It is a super-2 number, since 2×640100161² = 819456432224451842, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (640100141) 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, 320050080 + 320050081.

It is an arithmetic number, because the mean of its divisors is an integer number (320050081).

Almost surely, 2^640100161 is an apocalyptic number.

It is an amenable number.

640100161 is a deficient number, since it is larger than the sum of its proper divisors (1).

640100161 is an equidigital number, since it uses as much as digits as its factorization.

640100161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 640100161 is about 25300.2008094798. The cubic root of 640100161 is about 861.8188299871.

The spelling of 640100161 in words is "six hundred forty million, one hundred thousand, one hundred sixty-one".