640261243546263 has 24 divisors (see below), whose sum is σ = 948028255553808. Its totient is φ = 416165798345472.

The previous prime is 640261243546247. The next prime is 640261243546289. The reversal of 640261243546263 is 362645342162046.

640261243546263 is a `hidden beast` number, since 6 + 4 + 0 + 2 + 6 + 1 + 2 + 4 + 3 + 5 + 4 + 626 + 3 = 666.

It is not a de Polignac number, because 640261243546263 - 2⁴ = 640261243546247 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640261243546063) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1484902770 + ... + 1485333887.

It is an arithmetic number, because the mean of its divisors is an integer number (39501177314742).

Almost surely, 2^{640261243546263} is an apocalyptic number.

640261243546263 is a deficient number, since it is larger than the sum of its proper divisors (307767012007545).

640261243546263 is a wasteful number, since it uses less digits than its factorization.

640261243546263 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2970237263 (or 2970237260 counting only the distinct ones).

The product of its (nonzero) digits is 29859840, while the sum is 54.

The spelling of 640261243546263 in words is "six hundred forty trillion, two hundred sixty-one billion, two hundred forty-three million, five hundred forty-six thousand, two hundred sixty-three".