21326985 has 24 divisors (see below), whose sum is σ = 37968840. Its totient is φ = 11066112.

The previous prime is 21326953. The next prime is 21326989. The reversal of 21326985 is 58962312.

It can be written as a sum of positive squares in 4 ways, for example, as 4112784 + 17214201 = 2028^2 + 4149^2 .

It is not a de Polignac number, because 21326985 - 2⁵ = 21326953 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21326989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4740 + ... + 8069.

It is an arithmetic number, because the mean of its divisors is an integer number (1582035).

Almost surely, 2^21326985 is an apocalyptic number.

It is an amenable number.

21326985 is a deficient number, since it is larger than the sum of its proper divisors (16641855).

21326985 is a wasteful number, since it uses less digits than its factorization.

21326985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12857 (or 12854 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 21326985 is about 4618.1148751412. The cubic root of 21326985 is about 277.3169964579.

The spelling of 21326985 in words is "twenty-one million, three hundred twenty-six thousand, nine hundred eighty-five".