21000132 has 18 divisors (see below), whose sum is σ = 53083758. Its totient is φ = 7000032.

The previous prime is 21000131. The next prime is 21000139. The reversal of 21000132 is 23100012.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 18096516 + 2903616 = 4254^2 + 1704^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (9).

It is not an unprimeable number, because it can be changed into a prime (21000131) 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 5 ways as a sum of consecutive naturals, for example, 291633 + ... + 291704.

Almost surely, 2^21000132 is an apocalyptic number.

It is an amenable number.

21000132 is an abundant number, since it is smaller than the sum of its proper divisors (32083626).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21000132 is a wasteful number, since it uses less digits than its factorization.

21000132 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 583347 (or 583342 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 21000132 is about 4582.5900973140. The cubic root of 21000132 is about 275.8929956972.

Adding to 21000132 its reverse (23100012), we get a palindrome (44100144).

The spelling of 21000132 in words is "twenty-one million, one hundred thirty-two", and thus it is an aban number.