21212299 has 4 divisors (see below), whose sum is σ = 21228480. Its totient is φ = 21196120.

The previous prime is 21212297. The next prime is 21212353. The reversal of 21212299 is 99221212.

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

It is a cyclic number.

It is not a de Polignac number, because 21212299 - 2¹ = 21212297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21212291) 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, 5932 + ... + 8809.

It is an arithmetic number, because the mean of its divisors is an integer number (5307120).

Almost surely, 2^21212299 is an apocalyptic number.

21212299 is a deficient number, since it is larger than the sum of its proper divisors (16181).

21212299 is a wasteful number, since it uses less digits than its factorization.

21212299 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16180.

The product of its digits is 1296, while the sum is 28.

The square root of 21212299 is about 4605.6811656909. The cubic root of 21212299 is about 276.8190114341.

The spelling of 21212299 in words is "twenty-one million, two hundred twelve thousand, two hundred ninety-nine".