21086001 has 20 divisors (see below), whose sum is σ = 33353892. Its totient is φ = 13229568.

The previous prime is 21085993. The next prime is 21086003. The reversal of 21086001 is 10068012.

It can be written as a sum of positive squares in 2 ways, for example, as 5688225 + 15397776 = 2385^2 + 3924^2 .

It is not a de Polignac number, because 21086001 - 2³ = 21085993 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21086003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 6280 + ... + 9033.

Almost surely, 2^21086001 is an apocalyptic number.

It is an amenable number.

21086001 is a deficient number, since it is larger than the sum of its proper divisors (12267891).

21086001 is a wasteful number, since it uses less digits than its factorization.

21086001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15342 (or 15333 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 21086001 is about 4591.9495859602. The cubic root of 21086001 is about 276.2685241088.

The spelling of 21086001 in words is "twenty-one million, eighty-six thousand, one".