21051332 has 24 divisors (see below), whose sum is σ = 38367000. Its totient is φ = 10094336.

The previous prime is 21051323. The next prime is 21051337. The reversal of 21051332 is 23315012.

It can be written as a sum of positive squares in 4 ways, for example, as 12559936 + 8491396 = 3544^2 + 2914^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21051332.

It is not an unprimeable number, because it can be changed into a prime (21051337) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19544 + ... + 20592.

It is an arithmetic number, because the mean of its divisors is an integer number (1598625).

Almost surely, 2^21051332 is an apocalyptic number.

It is an amenable number.

21051332 is a deficient number, since it is larger than the sum of its proper divisors (17315668).

21051332 is a wasteful number, since it uses less digits than its factorization.

21051332 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1255 (or 1253 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 21051332 is about 4588.1730568931. The cubic root of 21051332 is about 276.1170301148.

Adding to 21051332 its reverse (23315012), we get a palindrome (44366344).

The spelling of 21051332 in words is "twenty-one million, fifty-one thousand, three hundred thirty-two".