21525571 has 2 divisors, whose sum is σ = 21525572. Its totient is φ = 21525570.

The previous prime is 21525551. The next prime is 21525641. The reversal of 21525571 is 17552512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21525571 - 2⁹ = 21525059 is a prime.

It is a super-3 number, since 3×21525571³ (a number of 23 digits) contains 333 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21525541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10762785 + 10762786.

It is an arithmetic number, because the mean of its divisors is an integer number (10762786).

Almost surely, 2^21525571 is an apocalyptic number.

21525571 is a deficient number, since it is larger than the sum of its proper divisors (1).

21525571 is an equidigital number, since it uses as much as digits as its factorization.

21525571 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3500, while the sum is 28.

The square root of 21525571 is about 4639.5658202034. The cubic root of 21525571 is about 278.1750833680.

The spelling of 21525571 in words is "twenty-one million, five hundred twenty-five thousand, five hundred seventy-one".