1009855 has 32 divisors (see below), whose sum is σ = 1571328. Its totient is φ = 604800.

The previous prime is 1009843. The next prime is 1009859. The reversal of 1009855 is 5589001.

It is not a de Polignac number, because 1009855 - 2⁷ = 1009727 is a prime.

It is a Smith number, since the sum of its digits (28) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1009859) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16525 + ... + 16585.

It is an arithmetic number, because the mean of its divisors is an integer number (49104).

2^1009855 is an apocalyptic number.

1009855 is a deficient number, since it is larger than the sum of its proper divisors (561473).

1009855 is a wasteful number, since it uses less digits than its factorization.

1009855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127.

The product of its (nonzero) digits is 1800, while the sum is 28.

The square root of 1009855 is about 1004.9154193264. The cubic root of 1009855 is about 100.3274267472.

It can be divided in two parts, 10098 and 55, that added together give a triangular number (10153 = T₁₄₂).

The spelling of 1009855 in words is "one million, nine thousand, eight hundred fifty-five".