21213299 has 4 divisors (see below), whose sum is σ = 21561120. Its totient is φ = 20865480.

The previous prime is 21213293. The next prime is 21213341. The reversal of 21213299 is 99231212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21213299 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21213293) 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, 173819 + ... + 173940.

It is an arithmetic number, because the mean of its divisors is an integer number (5390280).

Almost surely, 2^21213299 is an apocalyptic number.

21213299 is a deficient number, since it is larger than the sum of its proper divisors (347821).

21213299 is an equidigital number, since it uses as much as digits as its factorization.

21213299 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 347820.

The product of its digits is 1944, while the sum is 29.

The square root of 21213299 is about 4605.7897259862. The cubic root of 21213299 is about 276.8233613423.

It can be divided in two parts, 21213 and 299, that added together give a palindrome (21512).

The spelling of 21213299 in words is "twenty-one million, two hundred thirteen thousand, two hundred ninety-nine".