21144213 has 8 divisors (see below), whose sum is σ = 31324800. Its totient is φ = 14096124.

The previous prime is 21144203. The next prime is 21144223. The reversal of 21144213 is 31244112.

21144213 is a `hidden beast` number, since 211 + 442 + 13 = 666.

It is an interprime number because it is at equal distance from previous prime (21144203) and next prime (21144223).

It is not a de Polignac number, because 21144213 - 2⁵ = 21144181 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144203) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 391533 + ... + 391586.

It is an arithmetic number, because the mean of its divisors is an integer number (3915600).

Almost surely, 2^21144213 is an apocalyptic number.

It is an amenable number.

21144213 is a deficient number, since it is larger than the sum of its proper divisors (10180587).

21144213 is an equidigital number, since it uses as much as digits as its factorization.

21144213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 783128 (or 783122 counting only the distinct ones).

The product of its digits is 192, while the sum is 18.

The square root of 21144213 is about 4598.2837015565. The cubic root of 21144213 is about 276.5225214835.

Adding to 21144213 its reverse (31244112), we get a palindrome (52388325).

The spelling of 21144213 in words is "twenty-one million, one hundred forty-four thousand, two hundred thirteen".