1804661 has 4 divisors (see below), whose sum is σ = 1807392. Its totient is φ = 1801932.

The previous prime is 1804657. The next prime is 1804687. The reversal of 1804661 is 1664081.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1664081 = 127 ⋅13103.

It is a cyclic number.

It is not a de Polignac number, because 1804661 - 2² = 1804657 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 1804661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1804631) 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, 320 + ... + 1926.

It is an arithmetic number, because the mean of its divisors is an integer number (451848).

2^1804661 is an apocalyptic number.

It is an amenable number.

1804661 is a deficient number, since it is larger than the sum of its proper divisors (2731).

1804661 is a wasteful number, since it uses less digits than its factorization.

1804661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2730.

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 1804661 is about 1343.3767155940. The cubic root of 1804661 is about 121.7489462416.

The spelling of 1804661 in words is "one million, eight hundred four thousand, six hundred sixty-one".