640244402 has 8 divisors (see below), whose sum is σ = 1097561856. Its totient is φ = 274390452.

The previous prime is 640244369. The next prime is 640244431. The reversal of 640244402 is 204442046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-3 number, since 3×640244402³ (a number of 27 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22865858 + ... + 22865885.

It is an arithmetic number, because the mean of its divisors is an integer number (137195232).

Almost surely, 2^640244402 is an apocalyptic number.

640244402 is a deficient number, since it is larger than the sum of its proper divisors (457317454).

640244402 is a wasteful number, since it uses less digits than its factorization.

640244402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45731752.

The product of its (nonzero) digits is 6144, while the sum is 26.

The square root of 640244402 is about 25303.0512389316. The cubic root of 640244402 is about 861.8835595827.

Adding to 640244402 its reverse (204442046), we get a palindrome (844686448).

The spelling of 640244402 in words is "six hundred forty million, two hundred forty-four thousand, four hundred two".