21042562 has 12 divisors (see below), whose sum is σ = 32997510. Its totient is φ = 10063328.

The previous prime is 21042551. The next prime is 21042563. The reversal of 21042562 is 26524012.

It can be written as a sum of positive squares in only one way, i.e., 13039321 + 8003241 = 3611^2 + 2829^2 .

It is not an unprimeable number, because it can be changed into a prime (21042563) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8887 + ... + 11002.

Almost surely, 2^21042562 is an apocalyptic number.

21042562 is a deficient number, since it is larger than the sum of its proper divisors (11954948).

21042562 is a wasteful number, since it uses less digits than its factorization.

21042562 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19937 (or 19914 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 21042562 is about 4587.2172392421. The cubic root of 21042562 is about 276.0786812713.

Adding to 21042562 its reverse (26524012), we get a palindrome (47566574).

The spelling of 21042562 in words is "twenty-one million, forty-two thousand, five hundred sixty-two".