1644447420 has 240 divisors, whose sum is σ = 6432104448. Its totient is φ = 341677440.

The previous prime is 1644447379. The next prime is 1644447433. The reversal of 1644447420 is 247444461.

1644447420 is a `hidden beast` number, since 1 + 644 + 4 + 4 + 7 + 4 + 2 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 118149 + ... + 131331.

Almost surely, 2^1644447420 is an apocalyptic number.

1644447420 is a gapful number since it is divisible by the number (10) 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 1644447420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3216052224).

1644447420 is an abundant number, since it is smaller than the sum of its proper divisors (4787657028).

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

1644447420 is a wasteful number, since it uses less digits than its factorization.

1644447420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13222 (or 13211 counting only the distinct ones).

The product of its (nonzero) digits is 86016, while the sum is 36.

The square root of 1644447420 is about 40551.7868903455. The cubic root of 1644447420 is about 1180.3387469472.

The spelling of 1644447420 in words is "one billion, six hundred forty-four million, four hundred forty-seven thousand, four hundred twenty".