21542272 has 64 divisors (see below), whose sum is σ = 45532800. Its totient is φ = 10137600.

The previous prime is 21542263. The next prime is 21542299. The reversal of 21542272 is 27224512.

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-3 number, since 3×21542272³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 242004 + ... + 242092.

It is an arithmetic number, because the mean of its divisors is an integer number (711450).

Almost surely, 2^21542272 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 21542272, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22766400).

21542272 is an abundant number, since it is smaller than the sum of its proper divisors (23990528).

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

21542272 is an equidigital number, since it uses as much as digits as its factorization.

21542272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195 (or 183 counting only the distinct ones).

The product of its digits is 2240, while the sum is 25.

The square root of 21542272 is about 4641.3653163697. The cubic root of 21542272 is about 278.2470071446.

Adding to 21542272 its product of digits (2240), we get a palindrome (21544512).

Adding to 21542272 its reverse (27224512), we get a palindrome (48766784).

The spelling of 21542272 in words is "twenty-one million, five hundred forty-two thousand, two hundred seventy-two".