21552471 has 12 divisors (see below), whose sum is σ = 32136000. Its totient is φ = 13904640.

The previous prime is 21552469. The next prime is 21552473. The reversal of 21552471 is 17425512.

It is an interprime number because it is at equal distance from previous prime (21552469) and next prime (21552473).

It is not a de Polignac number, because 21552471 - 2¹ = 21552469 is a prime.

It is a super-3 number, since 3×21552471³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21552473) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 38346 + ... + 38903.

It is an arithmetic number, because the mean of its divisors is an integer number (2678000).

Almost surely, 2^21552471 is an apocalyptic number.

21552471 is a deficient number, since it is larger than the sum of its proper divisors (10583529).

21552471 is a wasteful number, since it uses less digits than its factorization.

21552471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77286 (or 77283 counting only the distinct ones).

The product of its digits is 2800, while the sum is 27.

The square root of 21552471 is about 4642.4638932360. The cubic root of 21552471 is about 278.2909114194.

Adding to 21552471 its reverse (17425512), we get a palindrome (38977983).

The spelling of 21552471 in words is "twenty-one million, five hundred fifty-two thousand, four hundred seventy-one".