21673392 has 80 divisors (see below), whose sum is σ = 61662720. Its totient is φ = 6518016.

The previous prime is 21673387. The next prime is 21673409. The reversal of 21673392 is 29337612.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28959 + ... + 29697.

It is an arithmetic number, because the mean of its divisors is an integer number (770784).

Almost surely, 2^21673392 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21673392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30831360).

21673392 is an abundant number, since it is smaller than the sum of its proper divisors (39989328).

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

21673392 is a wasteful number, since it uses less digits than its factorization.

21673392 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 810 (or 804 counting only the distinct ones).

The product of its digits is 13608, while the sum is 33.

The square root of 21673392 is about 4655.4690418904. The cubic root of 21673392 is about 278.8103951931.

The spelling of 21673392 in words is "twenty-one million, six hundred seventy-three thousand, three hundred ninety-two".