640620152609 has 2 divisors, whose sum is σ = 640620152610. Its totient is φ = 640620152608.

The previous prime is 640620152593. The next prime is 640620152707. The reversal of 640620152609 is 906251026046.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 574109290000 + 66510862609 = 757700^2 + 257897^2 .

It is a cyclic number.

It is not a de Polignac number, because 640620152609 - 2⁴ = 640620152593 is a prime.

It is not a weakly prime, because it can be changed into another prime (640620157609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320310076304 + 320310076305.

It is an arithmetic number, because the mean of its divisors is an integer number (320310076305).

Almost surely, 2^640620152609 is an apocalyptic number.

It is an amenable number.

640620152609 is a deficient number, since it is larger than the sum of its proper divisors (1).

640620152609 is an equidigital number, since it uses as much as digits as its factorization.

640620152609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 155520, while the sum is 41.

The spelling of 640620152609 in words is "six hundred forty billion, six hundred twenty million, one hundred fifty-two thousand, six hundred nine".