213444 has 81 divisors (see below), whose sum is σ = 689871. Its totient is φ = 55440.

The previous prime is 213407. The next prime is 213449. The reversal of 213444 is 444312.

213444 = T₁₁₂ + T₁₁₃ + ... + T₁₃₈.

The square root of 213444 is 462.

It is a perfect power (a square), and thus also a powerful number.

It is a super-2 number, since 2×213444² = 91116682272, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 213444.

It is not an unprimeable number, because it can be changed into a prime (213449) 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 26 ways as a sum of consecutive naturals, for example, 19399 + ... + 19409.

2²¹³⁴⁴⁴ is an apocalyptic number.

213444 is the 462-nd square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 213444

213444 is an abundant number, since it is smaller than the sum of its proper divisors (476427).

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

213444 is a wasteful number, since it uses less digits than its factorization.

213444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46 (or 23 counting only the distinct ones).

The product of its digits is 384, while the sum is 18.

The cubic root of 213444 is about 59.7623936290.

Adding to 213444 its reverse (444312), we get a palindrome (657756).

The spelling of 213444 in words is "two hundred thirteen thousand, four hundred forty-four".