213121361 has 4 divisors (see below), whose sum is σ = 214005924. Its totient is φ = 212236800.

The previous prime is 213121351. The next prime is 213121379. The reversal of 213121361 is 163121312.

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

It can be written as a sum of positive squares in 2 ways, for example, as 60450625 + 152670736 = 7775^2 + 12356^2 .

It is a cyclic number.

It is not a de Polignac number, because 213121361 - 2¹⁴ = 213104977 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (213121351) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 441920 + ... + 442401.

It is an arithmetic number, because the mean of its divisors is an integer number (53501481).

Almost surely, 2^213121361 is an apocalyptic number.

It is an amenable number.

213121361 is a deficient number, since it is larger than the sum of its proper divisors (884563).

213121361 is an equidigital number, since it uses as much as digits as its factorization.

213121361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 884562.

The product of its digits is 216, while the sum is 20.

The square root of 213121361 is about 14598.6766866042. The cubic root of 213121361 is about 597.3226644120.

Adding to 213121361 its reverse (163121312), we get a palindrome (376242673).

The spelling of 213121361 in words is "two hundred thirteen million, one hundred twenty-one thousand, three hundred sixty-one".