1644372 has 18 divisors (see below), whose sum is σ = 4156698. Its totient is φ = 548112.

The previous prime is 1644371. The next prime is 1644373. The reversal of 1644372 is 2734461.

It is an interprime number because it is at equal distance from previous prime (1644371) and next prime (1644373).

It can be written as a sum of positive squares in only one way, i.e., 1602756 + 41616 = 1266^2 + 204^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-3 number, since 3×1644372³ = 13338944759812100544, which contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1644371) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 22803 + ... + 22874.

2^1644372 is an apocalyptic number.

1644372 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1644372 is an abundant number, since it is smaller than the sum of its proper divisors (2512326).

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

1644372 is a wasteful number, since it uses less digits than its factorization.

1644372 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45687 (or 45682 counting only the distinct ones).

The product of its digits is 4032, while the sum is 27.

The square root of 1644372 is about 1282.3306905787. The cubic root of 1644372 is about 118.0320701877.

It can be divided in two parts, 1644 and 372, that added together give a triangular number (2016 = T₆₃).

The spelling of 1644372 in words is "one million, six hundred forty-four thousand, three hundred seventy-two".