210105 has 48 divisors (see below), whose sum is σ = 449280. Its totient is φ = 88704.

The previous prime is 210101. The next prime is 210109. The reversal of 210105 is 501012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (210101) and next prime (210109).

It is not a de Polignac number, because 210105 - 2² = 210101 is a prime.

It is a super-2 number, since 2×210105² = 88288222050, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an alternating number because its digits alternate between even and odd.

210105 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (210101) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7231 + ... + 7259.

It is an arithmetic number, because the mean of its divisors is an integer number (9360).

2²¹⁰¹⁰⁵ is an apocalyptic number.

It is an amenable number.

210105 is an abundant number, since it is smaller than the sum of its proper divisors (239175).

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

210105 is a wasteful number, since it uses less digits than its factorization.

210105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70 (or 67 counting only the distinct ones).

The product of its (nonzero) digits is 10, while the sum is 9.

The square root of 210105 is about 458.3721195710. The cubic root of 210105 is about 59.4491244136.

Adding to 210105 its reverse (501012), we get a palindrome (711117).

The spelling of 210105 in words is "two hundred ten thousand, one hundred five".