21673449 has 24 divisors (see below), whose sum is σ = 36459072. Its totient is φ = 12149280.

The previous prime is 21673423. The next prime is 21673459. The reversal of 21673449 is 94437612.

It is not a de Polignac number, because 21673449 - 2¹² = 21669353 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21673409) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 94 + ... + 6584.

It is an arithmetic number, because the mean of its divisors is an integer number (1519128).

Almost surely, 2^21673449 is an apocalyptic number.

It is an amenable number.

21673449 is a deficient number, since it is larger than the sum of its proper divisors (14785623).

21673449 is a wasteful number, since it uses less digits than its factorization.

21673449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6557 (or 6554 counting only the distinct ones).

The product of its digits is 36288, while the sum is 36.

The square root of 21673449 is about 4655.4751637185. The cubic root of 21673449 is about 278.8106396123.

It can be divided in two parts, 21673 and 449, that added together give a palindrome (22122).

The spelling of 21673449 in words is "twenty-one million, six hundred seventy-three thousand, four hundred forty-nine".