21486571 has 4 divisors (see below), whose sum is σ = 21892032. Its totient is φ = 21081112.

The previous prime is 21486559. The next prime is 21486581. The reversal of 21486571 is 17568412.

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 21486571 - 2⁵ = 21486539 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21486551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 202651 + ... + 202756.

It is an arithmetic number, because the mean of its divisors is an integer number (5473008).

Almost surely, 2^21486571 is an apocalyptic number.

21486571 is a deficient number, since it is larger than the sum of its proper divisors (405461).

21486571 is an equidigital number, since it uses as much as digits as its factorization.

21486571 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 405460.

The product of its digits is 13440, while the sum is 34.

The square root of 21486571 is about 4635.3609352455. The cubic root of 21486571 is about 278.0069827275.

The spelling of 21486571 in words is "twenty-one million, four hundred eighty-six thousand, five hundred seventy-one".