21409926 has 12 divisors (see below), whose sum is σ = 42842532. Its totient is φ = 7132864.

The previous prime is 21409909. The next prime is 21409931. The reversal of 21409926 is 62990412.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 10390 + ... + 12278.

It is an arithmetic number, because the mean of its divisors is an integer number (3570211).

Almost surely, 2^21409926 is an apocalyptic number.

21409926 is an abundant number, since it is smaller than the sum of its proper divisors (21432606).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21409926 is an frugal number, since it uses more digits than its factorization.

21409926 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3783 (or 1894 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 33.

The square root of 21409926 is about 4627.0861241174. The cubic root of 21409926 is about 277.6760282390.

Multiplying 21409926 by its product of nonzero digits (7776), we get a square (166483584576 = 408024²).

The spelling of 21409926 in words is "twenty-one million, four hundred nine thousand, nine hundred twenty-six".