21485571 has 4 divisors (see below), whose sum is σ = 28647432. Its totient is φ = 14323712.

The previous prime is 21485557. The next prime is 21485587. The reversal of 21485571 is 17558412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21485571 - 2⁵ = 21485539 is a prime.

It is a super-2 number, since 2×21485571² = 923259522392082, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21485591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3580926 + ... + 3580931.

It is an arithmetic number, because the mean of its divisors is an integer number (7161858).

Almost surely, 2^21485571 is an apocalyptic number.

21485571 is a deficient number, since it is larger than the sum of its proper divisors (7161861).

21485571 is an equidigital number, since it uses as much as digits as its factorization.

21485571 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7161860.

The product of its digits is 11200, while the sum is 33.

The square root of 21485571 is about 4635.2530675250. The cubic root of 21485571 is about 278.0026697810.

The spelling of 21485571 in words is "twenty-one million, four hundred eighty-five thousand, five hundred seventy-one".