21200985 has 24 divisors (see below), whose sum is σ = 39576264. Its totient is φ = 10437120.

The previous prime is 21200983. The next prime is 21200987. The reversal of 21200985 is 58900212.

It is an interprime number because it is at equal distance from previous prime (21200983) and next prime (21200987).

It can be written as a sum of positive squares in 4 ways, for example, as 1058841 + 20142144 = 1029^2 + 4488^2 .

It is not a de Polignac number, because 21200985 - 2¹ = 21200983 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21200983) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17536 + ... + 18705.

It is an arithmetic number, because the mean of its divisors is an integer number (1649011).

Almost surely, 2^21200985 is an apocalyptic number.

It is an amenable number.

21200985 is a deficient number, since it is larger than the sum of its proper divisors (18375279).

21200985 is a wasteful number, since it uses less digits than its factorization.

21200985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36265 (or 36262 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

The square root of 21200985 is about 4604.4527362109. The cubic root of 21200985 is about 276.7697870464.

The spelling of 21200985 in words is "twenty-one million, two hundred thousand, nine hundred eighty-five".