640565046 has 48 divisors (see below), whose sum is σ = 1526632848. Its totient is φ = 194103360.

The previous prime is 640565041. The next prime is 640565077.

It is a happy number.

640565046 is a `hidden beast` number, since 640 + 5 + 6 + 5 + 0 + 4 + 6 = 666.

640565046 is nontrivially palindromic in base 10.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 640565046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640565041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10590 + ... + 37326.

It is an arithmetic number, because the mean of its divisors is an integer number (31804851).

Almost surely, 2^640565046 is an apocalyptic number.

640565046 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 640565046, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (763316424).

640565046 is an abundant number, since it is smaller than the sum of its proper divisors (886067802).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640565046 is a wasteful number, since it uses less digits than its factorization.

640565046 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26778 (or 26753 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The square root of 640565046 is about 25309.3865196294. The cubic root of 640565046 is about 862.0274169749.

The spelling of 640565046 in words is "six hundred forty million, five hundred sixty-five thousand, forty-six".