21222471 has 4 divisors (see below), whose sum is σ = 28296632. Its totient is φ = 14148312.

The previous prime is 21222469. The next prime is 21222479. The reversal of 21222471 is 17422212.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21222471 - 2¹ = 21222469 is a prime.

It is a super-3 number, since 3×21222471³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222479) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3537076 + ... + 3537081.

It is an arithmetic number, because the mean of its divisors is an integer number (7074158).

Almost surely, 2^21222471 is an apocalyptic number.

21222471 is a deficient number, since it is larger than the sum of its proper divisors (7074161).

21222471 is an equidigital number, since it uses as much as digits as its factorization.

21222471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7074160.

The product of its digits is 448, while the sum is 21.

The square root of 21222471 is about 4606.7853216750. The cubic root of 21222471 is about 276.8632523249.

Adding to 21222471 its reverse (17422212), we get a palindrome (38644683).

The spelling of 21222471 in words is "twenty-one million, two hundred twenty-two thousand, four hundred seventy-one".