640461901 has 2 divisors, whose sum is σ = 640461902. Its totient is φ = 640461900.

The previous prime is 640461883. The next prime is 640461919. The reversal of 640461901 is 109164046.

It is a balanced prime because it is at equal distance from previous prime (640461883) and next prime (640461919).

It can be written as a sum of positive squares in only one way, i.e., 640039401 + 422500 = 25299^2 + 650^2 .

It is a cyclic number.

It is not a de Polignac number, because 640461901 - 2⁵ = 640461869 is a prime.

It is a congruent number.

It is a weakly prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320230950 + 320230951.

It is an arithmetic number, because the mean of its divisors is an integer number (320230951).

Almost surely, 2^640461901 is an apocalyptic number.

It is an amenable number.

640461901 is a deficient number, since it is larger than the sum of its proper divisors (1).

640461901 is an equidigital number, since it uses as much as digits as its factorization.

640461901 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.

The square root of 640461901 is about 25307.3487548577. The cubic root of 640461901 is about 861.9811460608.

The spelling of 640461901 in words is "six hundred forty million, four hundred sixty-one thousand, nine hundred one".