640540664205331 has 8 divisors (see below), whose sum is σ = 651397724598960. Its totient is φ = 629683618444032.

The previous prime is 640540664205271. The next prime is 640540664205347. The reversal of 640540664205331 is 133502466045046.

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 640540664205331 - 2⁷ = 640540664205203 is a prime.

It is a super-2 number, since 2×640540664205331² (a number of 30 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640540664200331) 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, 119454171 + ... + 124701163.

It is an arithmetic number, because the mean of its divisors is an integer number (81424715574870).

Almost surely, 2^{640540664205331} is an apocalyptic number.

640540664205331 is a deficient number, since it is larger than the sum of its proper divisors (10857060393629).

640540664205331 is a wasteful number, since it uses less digits than its factorization.

640540664205331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7316165.

The product of its (nonzero) digits is 6220800, while the sum is 49.

The spelling of 640540664205331 in words is "six hundred forty trillion, five hundred forty billion, six hundred sixty-four million, two hundred five thousand, three hundred thirty-one".