640251673 has 8 divisors (see below), whose sum is σ = 644313600. Its totient is φ = 636197520.

The previous prime is 640251643. The next prime is 640251691. The reversal of 640251673 is 376152046.

It is a happy number.

640251673 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640251673 - 2²¹ = 638154521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640251643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 303978 + ... + 306076.

It is an arithmetic number, because the mean of its divisors is an integer number (80539200).

Almost surely, 2^640251673 is an apocalyptic number.

It is an amenable number.

640251673 is a deficient number, since it is larger than the sum of its proper divisors (4061927).

640251673 is a wasteful number, since it uses less digits than its factorization.

640251673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3887.

The product of its (nonzero) digits is 30240, while the sum is 34.

The square root of 640251673 is about 25303.1949168480. The cubic root of 640251673 is about 861.8868222595.

The spelling of 640251673 in words is "six hundred forty million, two hundred fifty-one thousand, six hundred seventy-three".