213646 has 4 divisors (see below), whose sum is σ = 320472. Its totient is φ = 106822.

The previous prime is 213641. The next prime is 213649. The reversal of 213646 is 646312.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×213646² = 91289226632, which contains 22 as substring.

It is a Smith number, since the sum of its digits (22) 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 (213641) by changing a digit.

213646 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 53410 + ... + 53413.

It is an arithmetic number, because the mean of its divisors is an integer number (80118).

2²¹³⁶⁴⁶ is an apocalyptic number.

213646 is a deficient number, since it is larger than the sum of its proper divisors (106826).

213646 is a wasteful number, since it uses less digits than its factorization.

213646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106825.

The product of its digits is 864, while the sum is 22.

The square root of 213646 is about 462.2185630197. The cubic root of 213646 is about 59.7812404104.

Adding to 213646 its reverse (646312), we get a palindrome (859958).

The spelling of 213646 in words is "two hundred thirteen thousand, six hundred forty-six".