21471571 has 18 divisors (see below), whose sum is σ = 24558716. Its totient is φ = 18757200.

The previous prime is 21471533. The next prime is 21471589. The reversal of 21471571 is 17517412.

It is a de Polignac number, because none of the positive numbers 2^k-21471571 is a prime.

It is a super-2 number, since 2×21471571² = 922056722416082, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21471371) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 101656 + ... + 101866.

Almost surely, 2^21471571 is an apocalyptic number.

21471571 is a deficient number, since it is larger than the sum of its proper divisors (3087145).

21471571 is a wasteful number, since it uses less digits than its factorization.

21471571 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 291 (or 251 counting only the distinct ones).

The product of its digits is 1960, while the sum is 28.

The square root of 21471571 is about 4633.7426557805. The cubic root of 21471571 is about 277.9422744730.

Adding to 21471571 its reverse (17517412), we get a palindrome (38988983).

The spelling of 21471571 in words is "twenty-one million, four hundred seventy-one thousand, five hundred seventy-one".