1644332420 has 36 divisors (see below), whose sum is σ = 3519600420. Its totient is φ = 645300864.

The previous prime is 1644332413. The next prime is 1644332441. The reversal of 1644332420 is 242334461.

It can be written as a sum of positive squares in 6 ways, for example, as 80604484 + 1563727936 = 8978^2 + 39544^2 .

It is a super-3 number, since 3×1644332420³ (a number of 29 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 41546 + ... + 70814.

Almost surely, 2^1644332420 is an apocalyptic number.

1644332420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1644332420 is an abundant number, since it is smaller than the sum of its proper divisors (1875268000).

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

1644332420 is a wasteful number, since it uses less digits than its factorization.

1644332420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29384 (or 29329 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 29.

The square root of 1644332420 is about 40550.3689255721. The cubic root of 1644332420 is about 1180.3112317024.

Adding to 1644332420 its reverse (242334461), we get a palindrome (1886666881).

The spelling of 1644332420 in words is "one billion, six hundred forty-four million, three hundred thirty-two thousand, four hundred twenty".