640402226 has 8 divisors (see below), whose sum is σ = 960714540. Its totient is φ = 320164048.

The previous prime is 640402219. The next prime is 640402229. The reversal of 640402226 is 622204046.

It can be written as a sum of positive squares in 2 ways, for example, as 555780625 + 84621601 = 23575^2 + 9199^2 .

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

It is a super-2 number, since 2×640402226² = 820230022131510152, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 640402195 and 640402204.

It is not an unprimeable number, because it can be changed into a prime (640402229) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15740 + ... + 39096.

Almost surely, 2^640402226 is an apocalyptic number.

640402226 is a deficient number, since it is larger than the sum of its proper divisors (320312314).

640402226 is a wasteful number, since it uses less digits than its factorization.

640402226 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37068.

The product of its (nonzero) digits is 4608, while the sum is 26.

The square root of 640402226 is about 25306.1697220263. The cubic root of 640402226 is about 861.9543735484.

It can be divided in two parts, 64040 and 2226, that added together give a palindrome (66266).

The spelling of 640402226 in words is "six hundred forty million, four hundred two thousand, two hundred twenty-six".