21220774 has 16 divisors (see below), whose sum is σ = 32329440. Its totient is φ = 10445760.

The previous prime is 21220757. The next prime is 21220783. The reversal of 21220774 is 47702212.

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 7 ways as a sum of consecutive naturals, for example, 67642 + ... + 67954.

It is an arithmetic number, because the mean of its divisors is an integer number (2020590).

Almost surely, 2^21220774 is an apocalyptic number.

21220774 is a deficient number, since it is larger than the sum of its proper divisors (11108666).

21220774 is a wasteful number, since it uses less digits than its factorization.

21220774 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 735.

The product of its (nonzero) digits is 1568, while the sum is 25.

The square root of 21220774 is about 4606.6011331566. The cubic root of 21220774 is about 276.8558725769.

Adding to 21220774 its reverse (47702212), we get a palindrome (68922986).

The spelling of 21220774 in words is "twenty-one million, two hundred twenty thousand, seven hundred seventy-four".