640550188738907 has 4 divisors (see below), whose sum is σ = 641951830290216. Its totient is φ = 639148547187600.

The previous prime is 640550188738891. The next prime is 640550188738921. The reversal of 640550188738907 is 709837881055046.

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 640550188738907 - 2⁴ = 640550188738891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640550188731907) by changing a digit.

Being equal to 28×3²⁸-1, it is a generalized Woodall number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 700820774969 + ... + 700820775882.

It is an arithmetic number, because the mean of its divisors is an integer number (160487957572554).

Almost surely, 2^{640550188738907} is an apocalyptic number.

640550188738907 is a deficient number, since it is larger than the sum of its proper divisors (1401641551309).

640550188738907 is a wasteful number, since it uses less digits than its factorization.

640550188738907 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1401641551308.

The product of its (nonzero) digits is 406425600, while the sum is 71.

The spelling of 640550188738907 in words is "six hundred forty trillion, five hundred fifty billion, one hundred eighty-eight million, seven hundred thirty-eight thousand, nine hundred seven".