21046 has 8 divisors (see below), whose sum is σ = 33480. Its totient is φ = 9888.

The previous prime is 21031. The next prime is 21059. The reversal of 21046 is 64012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable 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 in 3 ways as a sum of consecutive naturals, for example, 276 + ... + 343.

It is an arithmetic number, because the mean of its divisors is an integer number (4185).

2²¹⁰⁴⁶ is an apocalyptic number.

21046 is a deficient number, since it is larger than the sum of its proper divisors (12434).

21046 is a wasteful number, since it uses less digits than its factorization.

21046 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 638.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 21046 is about 145.0723957202. The cubic root of 21046 is about 27.6093715987.

Adding to 21046 its reverse (64012), we get a palindrome (85058).

It can be divided in two parts, 210 and 46, that added together give a 8-th power (256 = 2⁸).

The spelling of 21046 in words is "twenty-one thousand, forty-six".