213511 has 4 divisors (see below), whose sum is σ = 216000. Its totient is φ = 211024.

The previous prime is 213491. The next prime is 213523. The reversal of 213511 is 115312.

213511 is nontrivially palindromic in base 4.

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

It is a cyclic number.

It is not a de Polignac number, because 213511 - 2⁷ = 213383 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 213491 and 213500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1111 + ... + 1288.

It is an arithmetic number, because the mean of its divisors is an integer number (54000).

2²¹³⁵¹¹ is an apocalyptic number.

213511 is a deficient number, since it is larger than the sum of its proper divisors (2489).

213511 is an equidigital number, since it uses as much as digits as its factorization.

213511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2488.

The product of its digits is 30, while the sum is 13.

The square root of 213511 is about 462.0725051331. The cubic root of 213511 is about 59.7686461066.

Adding to 213511 its reverse (115312), we get a palindrome (328823).

The spelling of 213511 in words is "two hundred thirteen thousand, five hundred eleven".