640213401901 has 2 divisors, whose sum is σ = 640213401902. Its totient is φ = 640213401900.

The previous prime is 640213401871. The next prime is 640213401907. The reversal of 640213401901 is 109104312046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 573088364676 + 67125037225 = 757026^2 + 259085^2 .

It is a cyclic number.

It is not a de Polignac number, because 640213401901 - 2²¹ = 640211304749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640213401907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320106700950 + 320106700951.

It is an arithmetic number, because the mean of its divisors is an integer number (320106700951).

Almost surely, 2^640213401901 is an apocalyptic number.

It is an amenable number.

640213401901 is a deficient number, since it is larger than the sum of its proper divisors (1).

640213401901 is an equidigital number, since it uses as much as digits as its factorization.

640213401901 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 31.

Adding to 640213401901 its reverse (109104312046), we get a palindrome (749317713947).

The spelling of 640213401901 in words is "six hundred forty billion, two hundred thirteen million, four hundred one thousand, nine hundred one".