21212396 has 24 divisors (see below), whose sum is σ = 40372416. Its totient is φ = 9711360.

The previous prime is 21212353. The next prime is 21212423. The reversal of 21212396 is 69321212.

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 7 ways as a sum of consecutive naturals, for example, 1700 + ... + 6731.

It is an arithmetic number, because the mean of its divisors is an integer number (1682184).

Almost surely, 2^21212396 is an apocalyptic number.

It is an amenable number.

21212396 is a deficient number, since it is larger than the sum of its proper divisors (19160020).

21212396 is a wasteful number, since it uses less digits than its factorization.

21212396 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8489 (or 8487 counting only the distinct ones).

The product of its digits is 1296, while the sum is 26.

The square root of 21212396 is about 4605.6916961516. The cubic root of 21212396 is about 276.8194333812.

The spelling of 21212396 in words is "twenty-one million, two hundred twelve thousand, three hundred ninety-six".