1663640 has 64 divisors (see below), whose sum is σ = 4320000. Its totient is φ = 570240.

The previous prime is 1663619. The next prime is 1663681. The reversal of 1663640 is 463661.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8261 + ... + 8459.

It is an arithmetic number, because the mean of its divisors is an integer number (67500).

2^1663640 is an apocalyptic number.

1663640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1663640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2160000).

1663640 is an abundant number, since it is smaller than the sum of its proper divisors (2656360).

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

1663640 is a wasteful number, since it uses less digits than its factorization.

1663640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240 (or 236 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 26.

The square root of 1663640 is about 1289.8216931034. The cubic root of 1663640 is about 118.4912964582.

The spelling of 1663640 in words is "one million, six hundred sixty-three thousand, six hundred forty".