21042572 has 6 divisors (see below), whose sum is σ = 36824508. Its totient is φ = 10521284.

The previous prime is 21042563. The next prime is 21042577. The reversal of 21042572 is 27524012.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21042577) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2630318 + ... + 2630325.

It is an arithmetic number, because the mean of its divisors is an integer number (6137418).

Almost surely, 2^21042572 is an apocalyptic number.

It is an amenable number.

21042572 is a deficient number, since it is larger than the sum of its proper divisors (15781936).

21042572 is a wasteful number, since it uses less digits than its factorization.

21042572 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5260647 (or 5260645 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 23.

The square root of 21042572 is about 4587.2183292274. The cubic root of 21042572 is about 276.0787250047.

Adding to 21042572 its reverse (27524012), we get a palindrome (48566584).

The spelling of 21042572 in words is "twenty-one million, forty-two thousand, five hundred seventy-two".