21288571 has 2 divisors, whose sum is σ = 21288572. Its totient is φ = 21288570.

The previous prime is 21288559. The next prime is 21288577. The reversal of 21288571 is 17588212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21288571 is a prime.

It is not a weakly prime, because it can be changed into another prime (21288577) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10644285 + 10644286.

It is an arithmetic number, because the mean of its divisors is an integer number (10644286).

Almost surely, 2^21288571 is an apocalyptic number.

21288571 is a deficient number, since it is larger than the sum of its proper divisors (1).

21288571 is an equidigital number, since it uses as much as digits as its factorization.

21288571 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8960, while the sum is 34.

The square root of 21288571 is about 4613.9539442868. The cubic root of 21288571 is about 277.1503959835.

The spelling of 21288571 in words is "twenty-one million, two hundred eighty-eight thousand, five hundred seventy-one".