21281032 has 16 divisors (see below), whose sum is σ = 40195260. Its totient is φ = 10562304.

The previous prime is 21281027. The next prime is 21281047. The reversal of 21281032 is 23018212.

It can be written as a sum of positive squares in 2 ways, for example, as 19131876 + 2149156 = 4374^2 + 1466^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8613 + ... + 10804.

Almost surely, 2^21281032 is an apocalyptic number.

It is an amenable number.

21281032 is a deficient number, since it is larger than the sum of its proper divisors (18914228).

21281032 is a wasteful number, since it uses less digits than its factorization.

21281032 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19560 (or 19556 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 21281032 is about 4613.1368936983. The cubic root of 21281032 is about 277.1176760242.

Adding to 21281032 its reverse (23018212), we get a palindrome (44299244).

It can be divided in two parts, 2128 and 1032, that added together give a triangular number (3160 = T₇₉).

The spelling of 21281032 in words is "twenty-one million, two hundred eighty-one thousand, thirty-two".