640620620231 has 4 divisors (see below), whose sum is σ = 674337495000. Its totient is φ = 606903745464.

The previous prime is 640620620209. The next prime is 640620620309. The reversal of 640620620231 is 132026026046.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 640620620231 - 2³⁰ = 639546878407 is a prime.

It is a super-2 number, since 2×640620620231² (a number of 24 digits) 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 (640620622231) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16858437356 + ... + 16858437393.

It is an arithmetic number, because the mean of its divisors is an integer number (168584373750).

Almost surely, 2^640620620231 is an apocalyptic number.

640620620231 is a deficient number, since it is larger than the sum of its proper divisors (33716874769).

640620620231 is a wasteful number, since it uses less digits than its factorization.

640620620231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33716874768.

The product of its (nonzero) digits is 20736, while the sum is 32.

Adding to 640620620231 its reverse (132026026046), we get a palindrome (772646646277).

The spelling of 640620620231 in words is "six hundred forty billion, six hundred twenty million, six hundred twenty thousand, two hundred thirty-one".