640662941 has 2 divisors, whose sum is σ = 640662942. Its totient is φ = 640662940.

The previous prime is 640662923. The next prime is 640662947. The reversal of 640662941 is 149266046.

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., 639331225 + 1331716 = 25285^2 + 1154^2 .

It is a cyclic number.

It is not a de Polignac number, because 640662941 - 2²⁶ = 573554077 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 640662895 and 640662904.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640662947) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320331470 + 320331471.

It is an arithmetic number, because the mean of its divisors is an integer number (320331471).

Almost surely, 2^640662941 is an apocalyptic number.

It is an amenable number.

640662941 is a deficient number, since it is larger than the sum of its proper divisors (1).

640662941 is an equidigital number, since it uses as much as digits as its factorization.

640662941 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 62208, while the sum is 38.

The square root of 640662941 is about 25311.3204120212. The cubic root of 640662941 is about 862.0713281416.

The spelling of 640662941 in words is "six hundred forty million, six hundred sixty-two thousand, nine hundred forty-one".