21673456 has 20 divisors (see below), whose sum is σ = 47991472. Its totient is φ = 9288576.

The previous prime is 21673423. The next prime is 21673459. The reversal of 21673456 is 65437612.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21673459) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 96645 + ... + 96868.

Almost surely, 2^21673456 is an apocalyptic number.

It is an amenable number.

21673456 is an abundant number, since it is smaller than the sum of its proper divisors (26318016).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21673456 is a wasteful number, since it uses less digits than its factorization.

21673456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 193528 (or 193522 counting only the distinct ones).

The product of its digits is 30240, while the sum is 34.

The square root of 21673456 is about 4655.4759155214. The cubic root of 21673456 is about 278.8106696287.

The spelling of 21673456 in words is "twenty-one million, six hundred seventy-three thousand, four hundred fifty-six".