21315572 has 24 divisors (see below), whose sum is σ = 39880512. Its totient is φ = 9944000.

The previous prime is 21315571. The next prime is 21315583. The reversal of 21315572 is 27551312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21315571) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 947 + ... + 6597.

It is an arithmetic number, because the mean of its divisors is an integer number (1661688).

Almost surely, 2^21315572 is an apocalyptic number.

It is an amenable number.

21315572 is a deficient number, since it is larger than the sum of its proper divisors (18564940).

21315572 is a wasteful number, since it uses less digits than its factorization.

21315572 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5719 (or 5717 counting only the distinct ones).

The product of its digits is 2100, while the sum is 26.

The square root of 21315572 is about 4616.8790324201. The cubic root of 21315572 is about 277.2675194904.

Adding to 21315572 its reverse (27551312), we get a palindrome (48866884).

The spelling of 21315572 in words is "twenty-one million, three hundred fifteen thousand, five hundred seventy-two".