21421199 has 4 divisors (see below), whose sum is σ = 21430464. Its totient is φ = 21411936.

The previous prime is 21421177. The next prime is 21421201. The reversal of 21421199 is 99112412.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21421199 - 2²⁴ = 4643983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21421159) 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, 2039 + ... + 6855.

It is an arithmetic number, because the mean of its divisors is an integer number (5357616).

Almost surely, 2^21421199 is an apocalyptic number.

21421199 is a deficient number, since it is larger than the sum of its proper divisors (9265).

21421199 is an equidigital number, since it uses as much as digits as its factorization.

21421199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9264.

The product of its digits is 1296, while the sum is 29.

The square root of 21421199 is about 4628.3041170606. The cubic root of 21421199 is about 277.7247547446.

The spelling of 21421199 in words is "twenty-one million, four hundred twenty-one thousand, one hundred ninety-nine".