21002132 has 6 divisors (see below), whose sum is σ = 36753738. Its totient is φ = 10501064.

The previous prime is 21002129. The next prime is 21002203. The reversal of 21002132 is 23120012.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20921476 + 80656 = 4574^2 + 284^2 .

It is a congruent number.

It is an unprimeable number.

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, 2625263 + ... + 2625270.

It is an arithmetic number, because the mean of its divisors is an integer number (6125623).

Almost surely, 2^21002132 is an apocalyptic number.

It is an amenable number.

21002132 is a deficient number, since it is larger than the sum of its proper divisors (15751606).

21002132 is a wasteful number, since it uses less digits than its factorization.

21002132 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5250537 (or 5250535 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 21002132 is about 4582.8083093230. The cubic root of 21002132 is about 275.9017538719.

Adding to 21002132 its reverse (23120012), we get a palindrome (44122144).

The spelling of 21002132 in words is "twenty-one million, two thousand, one hundred thirty-two".