1661600 has 72 divisors (see below), whose sum is σ = 4249728. Its totient is φ = 633600.

The previous prime is 1661599. The next prime is 1661623. The reversal of 1661600 is 61661.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 24767 + ... + 24833.

It is an arithmetic number, because the mean of its divisors is an integer number (59024).

2^1661600 is an apocalyptic number.

1661600 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 1661600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2124864).

1661600 is an abundant number, since it is smaller than the sum of its proper divisors (2588128).

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

1661600 is a wasteful number, since it uses less digits than its factorization.

1661600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118 (or 105 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 1661600 is about 1289.0306435458. The cubic root of 1661600 is about 118.4428442461.

It can be divided in two parts, 16 and 61600, that added together give a palindrome (61616).

The spelling of 1661600 in words is "one million, six hundred sixty-one thousand, six hundred".