21020746 has 8 divisors (see below), whose sum is σ = 31911264. Its totient is φ = 10383660.

The previous prime is 21020719. The next prime is 21020749. The reversal of 21020746 is 64702012.

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

It is not an unprimeable number, because it can be changed into a prime (21020749) by changing a digit.

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, 63150 + ... + 63481.

It is an arithmetic number, because the mean of its divisors is an integer number (3988908).

Almost surely, 2^21020746 is an apocalyptic number.

21020746 is a deficient number, since it is larger than the sum of its proper divisors (10890518).

21020746 is a wasteful number, since it uses less digits than its factorization.

21020746 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126716.

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 21020746 is about 4584.8387103583. The cubic root of 21020746 is about 275.9832395479.

Adding to 21020746 its reverse (64702012), we get a palindrome (85722758).

The spelling of 21020746 in words is "twenty-one million, twenty thousand, seven hundred forty-six".