21212774 has 8 divisors (see below), whose sum is σ = 34711848. Its totient is φ = 9642160.

The previous prime is 21212749. The next prime is 21212777. The reversal of 21212774 is 47721212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212777) by changing a digit.

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, 482087 + ... + 482130.

It is an arithmetic number, because the mean of its divisors is an integer number (4338981).

Almost surely, 2^21212774 is an apocalyptic number.

21212774 is a deficient number, since it is larger than the sum of its proper divisors (13499074).

21212774 is a wasteful number, since it uses less digits than its factorization.

21212774 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 964230.

The product of its digits is 1568, while the sum is 26.

The square root of 21212774 is about 4605.7327321502. The cubic root of 21212774 is about 276.8210776575.

Adding to 21212774 its reverse (47721212), we get a palindrome (68933986).

The spelling of 21212774 in words is "twenty-one million, two hundred twelve thousand, seven hundred seventy-four".