21213926 has 16 divisors (see below), whose sum is σ = 33785424. Its totient is φ = 9955584.

The previous prime is 21213923. The next prime is 21213931. The reversal of 21213926 is 62931212.

It is a junction number, because it is equal to n+sod(n) for n = 21213895 and 21213904.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213923) 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 7 ways as a sum of consecutive naturals, for example, 17186 + ... + 18378.

It is an arithmetic number, because the mean of its divisors is an integer number (2111589).

Almost surely, 2^21213926 is an apocalyptic number.

21213926 is a deficient number, since it is larger than the sum of its proper divisors (12571498).

21213926 is a wasteful number, since it uses less digits than its factorization.

21213926 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1735.

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

The square root of 21213926 is about 4605.8577919862. The cubic root of 21213926 is about 276.8260886650.

The spelling of 21213926 in words is "twenty-one million, two hundred thirteen thousand, nine hundred twenty-six".