21002471 has 8 divisors (see below), whose sum is σ = 24074400. Its totient is φ = 17948448.

The previous prime is 21002461. The next prime is 21002477. The reversal of 21002471 is 17420012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21002471 - 2¹⁰ = 21001447 is a prime.

It is a super-3 number, since 3×21002471³ (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 (21002477) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1856 + ... + 6741.

It is an arithmetic number, because the mean of its divisors is an integer number (3009300).

Almost surely, 2^21002471 is an apocalyptic number.

21002471 is a deficient number, since it is larger than the sum of its proper divisors (3071929).

21002471 is an equidigital number, since it uses as much as digits as its factorization.

21002471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8953.

The product of its (nonzero) digits is 112, while the sum is 17.

The square root of 21002471 is about 4582.8452952287. The cubic root of 21002471 is about 275.9032383274.

Adding to 21002471 its reverse (17420012), we get a palindrome (38422483).

The spelling of 21002471 in words is "twenty-one million, two thousand, four hundred seventy-one".