640153973 has 8 divisors (see below), whose sum is σ = 642603960. Its totient is φ = 637709760.

The previous prime is 640153967. The next prime is 640153991. The reversal of 640153973 is 379351046.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 4761124 + 635392849 = 2182^2 + 25207^2 .

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 640153973 - 2⁴ = 640153957 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 (640153903) 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, 394103 + ... + 395723.

It is an arithmetic number, because the mean of its divisors is an integer number (80325495).

Almost surely, 2^640153973 is an apocalyptic number.

It is an amenable number.

640153973 is a deficient number, since it is larger than the sum of its proper divisors (2449987).

640153973 is a wasteful number, since it uses less digits than its factorization.

640153973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2887.

The product of its (nonzero) digits is 68040, while the sum is 38.

The square root of 640153973 is about 25301.2642569497. The cubic root of 640153973 is about 861.8429797989.

The spelling of 640153973 in words is "six hundred forty million, one hundred fifty-three thousand, nine hundred seventy-three".