21102449 has 4 divisors (see below), whose sum is σ = 21133680. Its totient is φ = 21071220.

The previous prime is 21102439. The next prime is 21102451. The reversal of 21102449 is 94420112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21102449 - 2¹² = 21098353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21102409) 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, 14579 + ... + 15960.

It is an arithmetic number, because the mean of its divisors is an integer number (5283420).

Almost surely, 2^21102449 is an apocalyptic number.

It is an amenable number.

21102449 is a deficient number, since it is larger than the sum of its proper divisors (31231).

21102449 is an equidigital number, since it uses as much as digits as its factorization.

21102449 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31230.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 21102449 is about 4593.7401972685. The cubic root of 21102449 is about 276.3403392699.

The spelling of 21102449 in words is "twenty-one million, one hundred two thousand, four hundred forty-nine".