1644444040 has 16 divisors (see below), whose sum is σ = 3699999180. Its totient is φ = 657777600.

The previous prime is 1644444019. The next prime is 1644444071. The reversal of 1644444040 is 404444461.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 1641708324 + 2735716 = 40518^2 + 1654^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1644443993 and 1644444011.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20555511 + ... + 20555590.

Almost surely, 2^1644444040 is an apocalyptic number.

1644444040 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1644444040 is an abundant number, since it is smaller than the sum of its proper divisors (2055555140).

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

1644444040 is a wasteful number, since it uses less digits than its factorization.

1644444040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41111112 (or 41111108 counting only the distinct ones).

The product of its (nonzero) digits is 24576, while the sum is 31.

The square root of 1644444040 is about 40551.7452152185. The cubic root of 1644444040 is about 1180.3379382566.

The spelling of 1644444040 in words is "one billion, six hundred forty-four million, four hundred forty-four thousand, forty".