21128926 has 32 divisors (see below), whose sum is σ = 41307840. Its totient is φ = 7865856.

The previous prime is 21128923. The next prime is 21128941. The reversal of 21128926 is 62982112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21128923) 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 15 ways as a sum of consecutive naturals, for example, 321 + ... + 6508.

It is an arithmetic number, because the mean of its divisors is an integer number (1290870).

Almost surely, 2^21128926 is an apocalyptic number.

21128926 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21128926 is a deficient number, since it is larger than the sum of its proper divisors (20178914).

21128926 is a wasteful number, since it uses less digits than its factorization.

21128926 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6868.

The product of its digits is 3456, while the sum is 31.

The square root of 21128926 is about 4596.6211503669. The cubic root of 21128926 is about 276.4558646488.

The spelling of 21128926 in words is "twenty-one million, one hundred twenty-eight thousand, nine hundred twenty-six".