1660999 has 4 divisors (see below), whose sum is σ = 1748440. Its totient is φ = 1573560.

The previous prime is 1660963. The next prime is 1661003. The reversal of 1660999 is 9990661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1660999 - 2⁷ = 1660871 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1660199) 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, 43692 + ... + 43729.

It is an arithmetic number, because the mean of its divisors is an integer number (437110).

2^1660999 is an apocalyptic number.

1660999 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

1660999 is a deficient number, since it is larger than the sum of its proper divisors (87441).

1660999 is an equidigital number, since it uses as much as digits as its factorization.

1660999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87440.

The product of its (nonzero) digits is 26244, while the sum is 40.

The square root of 1660999 is about 1288.7975015494. The cubic root of 1660999 is about 118.4285622823.

The spelling of 1660999 in words is "one million, six hundred sixty thousand, nine hundred ninety-nine".