21985266 has 16 divisors (see below), whose sum is σ = 45043488. Its totient is φ = 7149600.

The previous prime is 21985259. The next prime is 21985273. The reversal of 21985266 is 66258912.

It is an interprime number because it is at equal distance from previous prime (21985259) and next prime (21985273).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44440 + ... + 44931.

It is an arithmetic number, because the mean of its divisors is an integer number (2815218).

Almost surely, 2^21985266 is an apocalyptic number.

21985266 is an abundant number, since it is smaller than the sum of its proper divisors (23058222).

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

21985266 is a wasteful number, since it uses less digits than its factorization.

21985266 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89417.

The product of its digits is 51840, while the sum is 39.

The square root of 21985266 is about 4688.8448470812. The cubic root of 21985266 is about 280.1413656905.

The spelling of 21985266 in words is "twenty-one million, nine hundred eighty-five thousand, two hundred sixty-six".