640402022 has 8 divisors (see below), whose sum is σ = 1034495616. Its totient is φ = 295570152.

The previous prime is 640401977. The next prime is 640402027. The reversal of 640402022 is 220204046.

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

It is a super-2 number, since 2×640402022² = 820229499563376968, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 640401985 and 640402003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640402027) 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, 12315398 + ... + 12315449.

It is an arithmetic number, because the mean of its divisors is an integer number (129311952).

Almost surely, 2^640402022 is an apocalyptic number.

640402022 is a deficient number, since it is larger than the sum of its proper divisors (394093594).

640402022 is a wasteful number, since it uses less digits than its factorization.

640402022 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24630862.

The product of its (nonzero) digits is 768, while the sum is 20.

The square root of 640402022 is about 25306.1656913883. The cubic root of 640402022 is about 861.9542820232.

Adding to 640402022 its reverse (220204046), we get a palindrome (860606068).

The spelling of 640402022 in words is "six hundred forty million, four hundred two thousand, twenty-two".