640441650 has 48 divisors (see below), whose sum is σ = 1589880384. Its totient is φ = 170614080.

The previous prime is 640441643. The next prime is 640441661. The reversal of 640441650 is 56144046.

It is a super-3 number, since 3×640441650³ (a number of 27 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 240627 + ... + 243273.

It is an arithmetic number, because the mean of its divisors is an integer number (33122508).

Almost surely, 2^640441650 is an apocalyptic number.

640441650 is an abundant number, since it is smaller than the sum of its proper divisors (949438734).

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

640441650 is a wasteful number, since it uses less digits than its factorization.

640441650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4275 (or 4270 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 30.

The square root of 640441650 is about 25306.9486505189. The cubic root of 640441650 is about 861.9720608656.

Adding to 640441650 its reverse (56144046), we get a palindrome (696585696).

The spelling of 640441650 in words is "six hundred forty million, four hundred forty-one thousand, six hundred fifty".