1100021 has 12 divisors (see below), whose sum is σ = 1247328. Its totient is φ = 967824.

The previous prime is 1100009. The next prime is 1100023. The reversal of 1100021 is 1200011.

It is a happy number.

It is not a de Polignac number, because 1100021 - 2⁶ = 1099957 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1099978 and 1100014.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1100023) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3746 + ... + 4028.

It is an arithmetic number, because the mean of its divisors is an integer number (103944).

2^1100021 is an apocalyptic number.

It is an amenable number.

1100021 is a deficient number, since it is larger than the sum of its proper divisors (147307).

1100021 is a wasteful number, since it uses less digits than its factorization.

1100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332 (or 319 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 5.

The square root of 1100021 is about 1048.8188594796. The cubic root of 1100021 is about 103.2286684470.

Adding to 1100021 its reverse (1200011), we get a palindrome (2300032).

Multiplying 1100021 by its reverse (1200011), we get a palindrome (1320037300231).

The spelling of 1100021 in words is "one million, one hundred thousand, twenty-one".