1820661 has 8 divisors (see below), whose sum is σ = 2505984. Its totient is φ = 1174560.

The previous prime is 1820647. The next prime is 1820669. The reversal of 1820661 is 1660281.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1820661 - 2⁵ = 1820629 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1820669) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9696 + ... + 9881.

It is an arithmetic number, because the mean of its divisors is an integer number (313248).

2^1820661 is an apocalyptic number.

It is an amenable number.

1820661 is a deficient number, since it is larger than the sum of its proper divisors (685323).

1820661 is a wasteful number, since it uses less digits than its factorization.

1820661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19611.

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 1820661 is about 1349.3187169828. The cubic root of 1820661 is about 122.1076940312.

The spelling of 1820661 in words is "one million, eight hundred twenty thousand, six hundred sixty-one".