640923073 has 8 divisors (see below), whose sum is σ = 739736640. Its totient is φ = 543922800.

The previous prime is 640923061. The next prime is 640923079. The reversal of 640923073 is 370329046.

640923073 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 a de Polignac number, because none of the positive numbers 2^k-640923073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640923079) 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, 452563 + ... + 453976.

It is an arithmetic number, because the mean of its divisors is an integer number (92467080).

Almost surely, 2^640923073 is an apocalyptic number.

It is an amenable number.

640923073 is a deficient number, since it is larger than the sum of its proper divisors (98813567).

640923073 is a wasteful number, since it uses less digits than its factorization.

640923073 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 906647.

The product of its (nonzero) digits is 27216, while the sum is 34.

The square root of 640923073 is about 25316.4585398511. The cubic root of 640923073 is about 862.1879895869.

The spelling of 640923073 in words is "six hundred forty million, nine hundred twenty-three thousand, seventy-three".