1644000140 has 24 divisors (see below), whose sum is σ = 3571449840. Its totient is φ = 634923968.

The previous prime is 1644000139. The next prime is 1644000157. The reversal of 1644000140 is 410004461.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1416662 + ... + 1417821.

It is an arithmetic number, because the mean of its divisors is an integer number (148810410).

Almost surely, 2^1644000140 is an apocalyptic number.

1644000140 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1644000140 is an abundant number, since it is smaller than the sum of its proper divisors (1927449700).

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

1644000140 is a wasteful number, since it uses less digits than its factorization.

1644000140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2834521 (or 2834519 counting only the distinct ones).

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

The square root of 1644000140 is about 40546.2715918492. The cubic root of 1644000140 is about 1180.2317221839.

The spelling of 1644000140 in words is "one billion, six hundred forty-four million, one hundred forty", and thus it is an aban number.