1661500 has 24 divisors (see below), whose sum is σ = 3629808. Its totient is φ = 664400.

The previous prime is 1661489. The next prime is 1661503. The reversal of 1661500 is 51661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1162 + ... + 2161.

It is an arithmetic number, because the mean of its divisors is an integer number (151242).

2^1661500 is an apocalyptic number.

1661500 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1661500 is an abundant number, since it is smaller than the sum of its proper divisors (1968308).

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

1661500 is a wasteful number, since it uses less digits than its factorization.

1661500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3342 (or 3330 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 1661500 is about 1288.9918541248. The cubic root of 1661500 is about 118.4404681183.

It can be divided in two parts, 16 and 61500, that added together give a palindrome (61516).

The spelling of 1661500 in words is "one million, six hundred sixty-one thousand, five hundred".