640493215 has 8 divisors (see below), whose sum is σ = 768793248. Its totient is φ = 512260320.

The previous prime is 640493197. The next prime is 640493219. The reversal of 640493215 is 512394046.

It is a happy number.

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

It is not a de Polignac number, because 640493215 - 2⁹ = 640492703 is a prime.

It is a super-2 number, since 2×640493215² = 820463116922072450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640493219) 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, 7369 + ... + 36541.

It is an arithmetic number, because the mean of its divisors is an integer number (96099156).

Almost surely, 2^640493215 is an apocalyptic number.

640493215 is a deficient number, since it is larger than the sum of its proper divisors (128300033).

640493215 is a wasteful number, since it uses less digits than its factorization.

640493215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33569.

The product of its (nonzero) digits is 25920, while the sum is 34.

The square root of 640493215 is about 25307.9674213478. The cubic root of 640493215 is about 861.9951940667.

The spelling of 640493215 in words is "six hundred forty million, four hundred ninety-three thousand, two hundred fifteen".