21385826 has 16 divisors (see below), whose sum is σ = 39994560. Its totient is φ = 8332080.

The previous prime is 21385823. The next prime is 21385843. The reversal of 21385826 is 62858312.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21385823) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 69281 + ... + 69588.

It is an arithmetic number, because the mean of its divisors is an integer number (2499660).

Almost surely, 2^21385826 is an apocalyptic number.

21385826 is a deficient number, since it is larger than the sum of its proper divisors (18608734).

21385826 is a wasteful number, since it uses less digits than its factorization.

21385826 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138889.

The product of its digits is 23040, while the sum is 35.

The square root of 21385826 is about 4624.4811600870. The cubic root of 21385826 is about 277.5718008075.

The spelling of 21385826 in words is "twenty-one million, three hundred eighty-five thousand, eight hundred twenty-six".