21609032 has 16 divisors (see below), whose sum is σ = 40890300. Its totient is φ = 10704960.

The previous prime is 21609019. The next prime is 21609037. The reversal of 21609032 is 23090612.

It can be written as a sum of positive squares in 2 ways, for example, as 21585316 + 23716 = 4646^2 + 154^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21608989 and 21609007.

It is not an unprimeable number, because it can be changed into a prime (21609037) 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 3 ways as a sum of consecutive naturals, for example, 11519 + ... + 13262.

Almost surely, 2^21609032 is an apocalyptic number.

It is an amenable number.

21609032 is a deficient number, since it is larger than the sum of its proper divisors (19281268).

21609032 is a wasteful number, since it uses less digits than its factorization.

21609032 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24896 (or 24892 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 21609032 is about 4648.5516023811. The cubic root of 21609032 is about 278.5341420430.

Adding to 21609032 its reverse (23090612), we get a palindrome (44699644).

The spelling of 21609032 in words is "twenty-one million, six hundred nine thousand, thirty-two".