21212572 has 12 divisors (see below), whose sum is σ = 38402280. Its totient is φ = 10240496.

The previous prime is 21212537. The next prime is 21212591. The reversal of 21212572 is 27521212.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 91318 + ... + 91549.

It is an arithmetic number, because the mean of its divisors is an integer number (3200190).

Almost surely, 2^21212572 is an apocalyptic number.

It is an amenable number.

21212572 is a deficient number, since it is larger than the sum of its proper divisors (17189708).

21212572 is a wasteful number, since it uses less digits than its factorization.

21212572 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 182900 (or 182898 counting only the distinct ones).

The product of its digits is 560, while the sum is 22.

The square root of 21212572 is about 4605.7108029055. The cubic root of 21212572 is about 276.8201989726.

Adding to 21212572 its reverse (27521212), we get a palindrome (48733784).

The spelling of 21212572 in words is "twenty-one million, two hundred twelve thousand, five hundred seventy-two".