1809906 has 16 divisors (see below), whose sum is σ = 4137024. Its totient is φ = 517104.

The previous prime is 1809901. The next prime is 1809911. The reversal of 1809906 is 6099081.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1809901) and next prime (1809911).

It is a super-3 number, since 3×1809906³ = 17786451563335948248, which contains 333 as substring.

It is an Ulam number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1809901) 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, 21505 + ... + 21588.

It is an arithmetic number, because the mean of its divisors is an integer number (258564).

2^1809906 is an apocalyptic number.

1809906 is an abundant number, since it is smaller than the sum of its proper divisors (2327118).

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

1809906 is a wasteful number, since it uses less digits than its factorization.

1809906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43105.

The product of its (nonzero) digits is 3888, while the sum is 33.

The square root of 1809906 is about 1345.3274694289. The cubic root of 1809906 is about 121.8667810368.

The spelling of 1809906 in words is "one million, eight hundred nine thousand, nine hundred six".