640465019 has 2 divisors, whose sum is σ = 640465020. Its totient is φ = 640465018.

The previous prime is 640465009. The next prime is 640465031. The reversal of 640465019 is 910564046.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 640465019 - 2⁸ = 640464763 is a prime.

It is a super-2 number, since 2×640465019² = 820390881125340722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 640465019.

It is not a weakly prime, because it can be changed into another prime (640465009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320232509 + 320232510.

It is an arithmetic number, because the mean of its divisors is an integer number (320232510).

Almost surely, 2^640465019 is an apocalyptic number.

640465019 is a deficient number, since it is larger than the sum of its proper divisors (1).

640465019 is an equidigital number, since it uses as much as digits as its factorization.

640465019 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 35.

The square root of 640465019 is about 25307.4103574427. The cubic root of 640465019 is about 861.9825448704.

The spelling of 640465019 in words is "six hundred forty million, four hundred sixty-five thousand, nineteen".