421640660 has 48 divisors (see below), whose sum is σ = 1021991040. Its totient is φ = 143126400.

The previous prime is 421640651. The next prime is 421640683. The reversal of 421640660 is 66046124.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 770 + ... + 29049.

It is an arithmetic number, because the mean of its divisors is an integer number (21291480).

Almost surely, 2^421640660 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 421640660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (510995520).

421640660 is an abundant number, since it is smaller than the sum of its proper divisors (600350380).

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

421640660 is a wasteful number, since it uses less digits than its factorization.

421640660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29936 (or 29934 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 29.

The square root of 421640660 is about 20533.8905227431. The cubic root of 421640660 is about 749.8611061314.

Adding to 421640660 its reverse (66046124), we get a palindrome (487686784).

The spelling of 421640660 in words is "four hundred twenty-one million, six hundred forty thousand, six hundred sixty".