21025571 has 16 divisors (see below), whose sum is σ = 25536000. Its totient is φ = 16910208.

The previous prime is 21025561. The next prime is 21025601. The reversal of 21025571 is 17552012.

It is a happy number.

It is not a de Polignac number, because 21025571 - 2⁶ = 21025507 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21025561) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14330 + ... + 15728.

It is an arithmetic number, because the mean of its divisors is an integer number (1596000).

Almost surely, 2^21025571 is an apocalyptic number.

21025571 is a deficient number, since it is larger than the sum of its proper divisors (4510429).

21025571 is a wasteful number, since it uses less digits than its factorization.

21025571 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1538.

The product of its (nonzero) digits is 700, while the sum is 23.

The square root of 21025571 is about 4585.3648709781. The cubic root of 21025571 is about 276.0043538836.

Adding to 21025571 its reverse (17552012), we get a palindrome (38577583).

The spelling of 21025571 in words is "twenty-one million, twenty-five thousand, five hundred seventy-one".