21292 has 6 divisors (see below), whose sum is σ = 37268. Its totient is φ = 10644.

The previous prime is 21283. The next prime is 21313. The reversal of 21292 is 29212.

It is a happy number.

It is an alternating number because its digits alternate between even and odd.

It is an unprimeable number.

21292 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2658 + ... + 2665.

2²¹²⁹² is an apocalyptic number.

It is an amenable number.

21292 is a deficient number, since it is larger than the sum of its proper divisors (15976).

21292 is a wasteful number, since it uses less digits than its factorization.

21292 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5327 (or 5325 counting only the distinct ones).

The product of its digits is 72, while the sum is 16.

The square root of 21292 is about 145.9177850709. The cubic root of 21292 is about 27.7165275606.

It can be divided in two parts, 21 and 292, that added together give a palindrome (313).

The spelling of 21292 in words is "twenty-one thousand, two hundred ninety-two".