641544420 has 144 divisors (see below), whose sum is σ = 1997017344. Its totient is φ = 153753600.

The previous prime is 641544403. The next prime is 641544479. The reversal of 641544420 is 24445146.

It is a happy number.

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

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 703765 + ... + 704675.

It is an arithmetic number, because the mean of its divisors is an integer number (13868176).

Almost surely, 2^641544420 is an apocalyptic number.

641544420 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 641544420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (998508672).

641544420 is an abundant number, since it is smaller than the sum of its proper divisors (1355472924).

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

641544420 is a wasteful number, since it uses less digits than its factorization.

641544420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1042 (or 1029 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 30.

The square root of 641544420 is about 25328.7271689677. The cubic root of 641544420 is about 862.4665174988.

Adding to 641544420 its reverse (24445146), we get a palindrome (665989566).

The spelling of 641544420 in words is "six hundred forty-one million, five hundred forty-four thousand, four hundred twenty".