640251142309 has 4 divisors (see below), whose sum is σ = 640347383916. Its totient is φ = 640154900704.

The previous prime is 640251142291. The next prime is 640251142339. The reversal of 640251142309 is 903241152046.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 174201890625 + 466049251684 = 417375^2 + 682678^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640251142309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640251142339) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 48110824 + ... + 48124129.

It is an arithmetic number, because the mean of its divisors is an integer number (160086845979).

Almost surely, 2^640251142309 is an apocalyptic number.

It is an amenable number.

640251142309 is a deficient number, since it is larger than the sum of its proper divisors (96241607).

640251142309 is an equidigital number, since it uses as much as digits as its factorization.

640251142309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96241606.

The product of its (nonzero) digits is 51840, while the sum is 37.

The spelling of 640251142309 in words is "six hundred forty billion, two hundred fifty-one million, one hundred forty-two thousand, three hundred nine".