21036449 has 4 divisors (see below), whose sum is σ = 24041664. Its totient is φ = 18031236.

The previous prime is 21036443. The next prime is 21036451. The reversal of 21036449 is 94463012.

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 a de Polignac number, because none of the positive numbers 2^k-21036449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21036443) 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, 1502597 + ... + 1502610.

It is an arithmetic number, because the mean of its divisors is an integer number (6010416).

Almost surely, 2^21036449 is an apocalyptic number.

It is an amenable number.

21036449 is a deficient number, since it is larger than the sum of its proper divisors (3005215).

21036449 is an equidigital number, since it uses as much as digits as its factorization.

21036449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3005214.

The product of its (nonzero) digits is 5184, while the sum is 29.

The square root of 21036449 is about 4586.5508827440. The cubic root of 21036449 is about 276.0519444695.

The spelling of 21036449 in words is "twenty-one million, thirty-six thousand, four hundred forty-nine".