21726471 has 12 divisors (see below), whose sum is σ = 31369128. Its totient is φ = 13369824.

The previous prime is 21726461. The next prime is 21726473. The reversal of 21726471 is 17462712.

It is not a de Polignac number, because 21726471 - 2¹⁰ = 21725447 is a prime.

It is a super-3 number, since 3×21726471³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21726473) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 20920 + ... + 21933.

It is an arithmetic number, because the mean of its divisors is an integer number (2614094).

Almost surely, 2^21726471 is an apocalyptic number.

21726471 is a deficient number, since it is larger than the sum of its proper divisors (9642657).

21726471 is a wasteful number, since it uses less digits than its factorization.

21726471 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42882 (or 42869 counting only the distinct ones).

The product of its digits is 4704, while the sum is 30.

The square root of 21726471 is about 4661.1662703662. The cubic root of 21726471 is about 279.0378155600.

The spelling of 21726471 in words is "twenty-one million, seven hundred twenty-six thousand, four hundred seventy-one".