1661904 has 40 divisors (see below), whose sum is σ = 4771520. Its totient is φ = 553824.

The previous prime is 1661899. The next prime is 1661917. The reversal of 1661904 is 4091661.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

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, 1492 + ... + 2355.

It is an arithmetic number, because the mean of its divisors is an integer number (119288).

2^1661904 is an apocalyptic number.

It is an amenable number.

1661904 is an abundant number, since it is smaller than the sum of its proper divisors (3109616).

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

1661904 is a wasteful number, since it uses less digits than its factorization.

1661904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3864 (or 3852 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 1661904 is about 1289.1485562184. The cubic root of 1661904 is about 118.4500670894.

The spelling of 1661904 in words is "one million, six hundred sixty-one thousand, nine hundred four".