1644020100 has 54 divisors (see below), whose sum is σ = 5153092490. Its totient is φ = 438405120.

The previous prime is 1644020069. The next prime is 1644020107. The reversal of 1644020100 is 10204461.

1644020100 is a `hidden beast` number, since 1 + 644 + 0 + 20 + 1 + 0 + 0 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 58706244 + 1585313856 = 7662^2 + 39816^2 .

It is a super-3 number, since 3×1644020100³ (a number of 29 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (1644020107) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 912445 + ... + 914244.

Almost surely, 2^1644020100 is an apocalyptic number.

1644020100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1644020100 is an abundant number, since it is smaller than the sum of its proper divisors (3509072390).

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

1644020100 is a wasteful number, since it uses less digits than its factorization.

1644020100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1826709 (or 1826699 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 1644020100 is about 40546.5177296399. The cubic root of 1644020100 is about 1180.2364986089.

Adding to 1644020100 its reverse (10204461), we get a palindrome (1654224561).

The spelling of 1644020100 in words is "one billion, six hundred forty-four million, twenty thousand, one hundred".