21992472 has 72 divisors (see below), whose sum is σ = 61998300. Its totient is φ = 7313328.

The previous prime is 21992461. The next prime is 21992501. The reversal of 21992472 is 27429912.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 52279 + ... + 52697.

Almost surely, 2^21992472 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 21992472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30999150).

21992472 is an abundant number, since it is smaller than the sum of its proper divisors (40005828).

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

21992472 is an frugal number, since it uses more digits than its factorization.

21992472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 449 (or 424 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 21992472 is about 4689.6132036662. The cubic root of 21992472 is about 280.1719691890.

The spelling of 21992472 in words is "twenty-one million, nine hundred ninety-two thousand, four hundred seventy-two".