21206132 has 6 divisors (see below), whose sum is σ = 37110738. Its totient is φ = 10603064.

The previous prime is 21206131. The next prime is 21206173. The reversal of 21206132 is 23160212.

It can be written as a sum of positive squares in only one way, i.e., 15085456 + 6120676 = 3884^2 + 2474^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21206132.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21206131) 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 as a sum of consecutive naturals, namely, 2650763 + ... + 2650770.

It is an arithmetic number, because the mean of its divisors is an integer number (6185123).

Almost surely, 2^21206132 is an apocalyptic number.

It is an amenable number.

21206132 is a deficient number, since it is larger than the sum of its proper divisors (15904606).

21206132 is a wasteful number, since it uses less digits than its factorization.

21206132 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5301537 (or 5301535 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 21206132 is about 4605.0116177921. The cubic root of 21206132 is about 276.7921825284.

Adding to 21206132 its reverse (23160212), we get a palindrome (44366344).

The spelling of 21206132 in words is "twenty-one million, two hundred six thousand, one hundred thirty-two".