640886139 has 24 divisors (see below), whose sum is σ = 953993040. Its totient is φ = 414289728.

The previous prime is 640886087. The next prime is 640886161. The reversal of 640886139 is 931688046.

It is not a de Polignac number, because 640886139 - 2⁷ = 640886011 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 640886094 and 640886103.

It is not an unprimeable number, because it can be changed into a prime (640886039) 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, 99097 + ... + 105365.

It is an arithmetic number, because the mean of its divisors is an integer number (39749710).

Almost surely, 2^640886139 is an apocalyptic number.

640886139 is a deficient number, since it is larger than the sum of its proper divisors (313106901).

640886139 is a wasteful number, since it uses less digits than its factorization.

640886139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6619 (or 6616 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The square root of 640886139 is about 25315.7290829239. The cubic root of 640886139 is about 862.1714277122.

The spelling of 640886139 in words is "six hundred forty million, eight hundred eighty-six thousand, one hundred thirty-nine".