1644140 has 12 divisors (see below), whose sum is σ = 3452736. Its totient is φ = 657648.

The previous prime is 1644103. The next prime is 1644143. The reversal of 1644140 is 414461.

It is a happy number.

It is a super-3 number, since 3×1644140³ = 13333299689369832000, which contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 82207 = 1644140 / (1 + 6 + 4 + 4 + 1 + 4 + 0).

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (1644143) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41084 + ... + 41123.

It is an arithmetic number, because the mean of its divisors is an integer number (287728).

2^1644140 is an apocalyptic number.

1644140 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1644140 is an abundant number, since it is smaller than the sum of its proper divisors (1808596).

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

1644140 is a wasteful number, since it uses less digits than its factorization.

1644140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82216 (or 82214 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 1644140 is about 1282.2402271026. The cubic root of 1644140 is about 118.0265189847.

The spelling of 1644140 in words is "one million, six hundred forty-four thousand, one hundred forty".