640324255661 has 8 divisors (see below), whose sum is σ = 642159524160. Its totient is φ = 638491605472.

The previous prime is 640324255603. The next prime is 640324255687. The reversal of 640324255661 is 166552423046.

It is a happy number.

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 640324255661 - 2¹⁰ = 640324254637 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 (640324252661) 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, 164240 + ... + 1143513.

It is an arithmetic number, because the mean of its divisors is an integer number (80269940520).

Almost surely, 2^640324255661 is an apocalyptic number.

It is an amenable number.

640324255661 is a deficient number, since it is larger than the sum of its proper divisors (1835268499).

640324255661 is a wasteful number, since it uses less digits than its factorization.

640324255661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1309155.

The product of its (nonzero) digits is 1036800, while the sum is 44.

The spelling of 640324255661 in words is "six hundred forty billion, three hundred twenty-four million, two hundred fifty-five thousand, six hundred sixty-one".