21042964 has 12 divisors (see below), whose sum is σ = 36880564. Its totient is φ = 10505664.

The previous prime is 21042947. The next prime is 21042971. The reversal of 21042964 is 46924012.

It can be written as a sum of positive squares in 2 ways, for example, as 20178064 + 864900 = 4492^2 + 930^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 657 + ... + 6520.

Almost surely, 2^21042964 is an apocalyptic number.

It is an amenable number.

21042964 is a deficient number, since it is larger than the sum of its proper divisors (15837600).

21042964 is a wasteful number, since it uses less digits than its factorization.

21042964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7914 (or 7912 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 21042964 is about 4587.2610564475. The cubic root of 21042964 is about 276.0804393419.

Adding to 21042964 its reverse (46924012), we get a palindrome (67966976).

The spelling of 21042964 in words is "twenty-one million, forty-two thousand, nine hundred sixty-four".