21252771 has 18 divisors (see below), whose sum is σ = 32614452. Its totient is φ = 13333440.

The previous prime is 21252769. The next prime is 21252779. The reversal of 21252771 is 17725212.

It is not a de Polignac number, because 21252771 - 2¹ = 21252769 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21252779) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1485 + ... + 6686.

It is an arithmetic number, because the mean of its divisors is an integer number (1811914).

Almost surely, 2^21252771 is an apocalyptic number.

21252771 is a deficient number, since it is larger than the sum of its proper divisors (11361681).

21252771 is a wasteful number, since it uses less digits than its factorization.

21252771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8211 (or 8191 counting only the distinct ones).

The product of its digits is 1960, while the sum is 27.

The square root of 21252771 is about 4610.0727759982. The cubic root of 21252771 is about 276.9949518384.

Adding to 21252771 its reverse (17725212), we get a palindrome (38977983).

The spelling of 21252771 in words is "twenty-one million, two hundred fifty-two thousand, seven hundred seventy-one".