640147841 has 4 divisors (see below), whose sum is σ = 657449172. Its totient is φ = 622846512.

The previous prime is 640147819. The next prime is 640147853. The reversal of 640147841 is 148741046.

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

It can be written as a sum of positive squares in 2 ways, for example, as 603193600 + 36954241 = 24560^2 + 6079^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640147841 is a prime.

It is a super-2 number, since 2×640147841² = 819578516673922562, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640147141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8650610 + ... + 8650683.

It is an arithmetic number, because the mean of its divisors is an integer number (164362293).

Almost surely, 2^640147841 is an apocalyptic number.

It is an amenable number.

640147841 is a deficient number, since it is larger than the sum of its proper divisors (17301331).

640147841 is a wasteful number, since it uses less digits than its factorization.

640147841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17301330.

The product of its (nonzero) digits is 21504, while the sum is 35.

The square root of 640147841 is about 25301.1430769442. The cubic root of 640147841 is about 861.8402279412.

Adding to 640147841 its reverse (148741046), we get a palindrome (788888887).

The spelling of 640147841 in words is "six hundred forty million, one hundred forty-seven thousand, eight hundred forty-one".