213123321 has 12 divisors (see below), whose sum is σ = 308524372. Its totient is φ = 141768576.

The previous prime is 213123319. The next prime is 213123331. The reversal of 213123321 is 123321312.

213123321 is a `hidden beast` number, since 21 + 312 + 332 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 135489600 + 77633721 = 11640^2 + 8811^2 .

It is not a de Polignac number, because 213123321 - 2¹ = 213123319 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 213123294 and 213123303.

It is not an unprimeable number, because it can be changed into a prime (213123301) 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, 21796 + ... + 30021.

Almost surely, 2^213123321 is an apocalyptic number.

It is an amenable number.

213123321 is a deficient number, since it is larger than the sum of its proper divisors (95401051).

213123321 is a wasteful number, since it uses less digits than its factorization.

213123321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52280 (or 52277 counting only the distinct ones).

The product of its digits is 216, while the sum is 18.

The square root of 213123321 is about 14598.7438158220. The cubic root of 213123321 is about 597.3244955265.

Adding to 213123321 its reverse (123321312), we get a palindrome (336444633).

It can be divided in two parts, 213123 and 321, that added together give a square (213444 = 462²).

The spelling of 213123321 in words is "two hundred thirteen million, one hundred twenty-three thousand, three hundred twenty-one".