21453449 has 2 divisors, whose sum is σ = 21453450. Its totient is φ = 21453448.

The previous prime is 21453433. The next prime is 21453469. The reversal of 21453449 is 94435412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16345849 + 5107600 = 4043^2 + 2260^2 .

It is a cyclic number.

It is not a de Polignac number, because 21453449 - 2⁴ = 21453433 is a prime.

It is not a weakly prime, because it can be changed into another prime (21453469) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10726724 + 10726725.

It is an arithmetic number, because the mean of its divisors is an integer number (10726725).

Almost surely, 2^21453449 is an apocalyptic number.

It is an amenable number.

21453449 is a deficient number, since it is larger than the sum of its proper divisors (1).

21453449 is an equidigital number, since it uses as much as digits as its factorization.

21453449 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17280, while the sum is 32.

The square root of 21453449 is about 4631.7868042474. The cubic root of 21453449 is about 277.8640580630.

The spelling of 21453449 in words is "twenty-one million, four hundred fifty-three thousand, four hundred forty-nine".