21232775 has 6 divisors (see below), whose sum is σ = 26328672. Its totient is φ = 16986200.

The previous prime is 21232741. The next prime is 21232777. The reversal of 21232775 is 57723212.

It is not a de Polignac number, because 21232775 - 2¹⁶ = 21167239 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21232777) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 424631 + ... + 424680.

It is an arithmetic number, because the mean of its divisors is an integer number (4388112).

Almost surely, 2^21232775 is an apocalyptic number.

21232775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21232775 is a deficient number, since it is larger than the sum of its proper divisors (5095897).

21232775 is an equidigital number, since it uses as much as digits as its factorization.

21232775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 849321 (or 849316 counting only the distinct ones).

The product of its digits is 5880, while the sum is 29.

The square root of 21232775 is about 4607.9035363167. The cubic root of 21232775 is about 276.9080529104.

Adding to 21232775 its reverse (57723212), we get a palindrome (78955987).

The spelling of 21232775 in words is "twenty-one million, two hundred thirty-two thousand, seven hundred seventy-five".