1858221 has 14 divisors (see below), whose sum is σ = 2787150. Its totient is φ = 1238328.

The previous prime is 1858217. The next prime is 1858249. The reversal of 1858221 is 1228581.

It can be written as a sum of positive squares in only one way, i.e., 1822500 + 35721 = 1350^2 + 189^2 .

It is not a de Polignac number, because 1858221 - 2² = 1858217 is a prime.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1858201) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 546 + ... + 2003.

2^1858221 is an apocalyptic number.

1858221 is the 729-th nonagonal number.

It is an amenable number.

1858221 is a deficient number, since it is larger than the sum of its proper divisors (928929).

1858221 is an frugal number, since it uses more digits than its factorization.

1858221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2567 (or 2552 counting only the distinct ones).

The product of its digits is 1280, while the sum is 27.

The square root of 1858221 is about 1363.1658006273. The cubic root of 1858221 is about 122.9416737144.

The spelling of 1858221 in words is "one million, eight hundred fifty-eight thousand, two hundred twenty-one".