21105232 has 10 divisors (see below), whose sum is σ = 40891418. Its totient is φ = 10552608.

The previous prime is 21105229. The next prime is 21105233. The reversal of 21105232 is 23250112.

It can be written as a sum of positive squares in only one way, i.e., 12787776 + 8317456 = 3576^2 + 2884^2 .

It is a Harshad number since it is a multiple of its sum of digits (16), and also a Moran number because the ratio is a prime number: 1319077 = 21105232 / (2 + 1 + 1 + 0 + 5 + 2 + 3 + 2).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21105233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 659523 + ... + 659554.

Almost surely, 2^21105232 is an apocalyptic number.

It is an amenable number.

21105232 is a deficient number, since it is larger than the sum of its proper divisors (19786186).

21105232 is a wasteful number, since it uses less digits than its factorization.

21105232 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1319085 (or 1319079 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21105232 is about 4594.0430994931. The cubic root of 21105232 is about 276.3524866966.

Adding to 21105232 its reverse (23250112), we get a palindrome (44355344).

The spelling of 21105232 in words is "twenty-one million, one hundred five thousand, two hundred thirty-two".