21086983 has 4 divisors (see below), whose sum is σ = 21097440. Its totient is φ = 21076528.

The previous prime is 21086981. The next prime is 21087019. The reversal of 21086983 is 38968012.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21086983 - 2¹ = 21086981 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21086981) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1135 + ... + 6592.

It is an arithmetic number, because the mean of its divisors is an integer number (5274360).

Almost surely, 2^21086983 is an apocalyptic number.

21086983 is a deficient number, since it is larger than the sum of its proper divisors (10457).

21086983 is an equidigital number, since it uses as much as digits as its factorization.

21086983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10456.

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 21086983 is about 4592.0565109763. The cubic root of 21086983 is about 276.2728127595.

The spelling of 21086983 in words is "twenty-one million, eighty-six thousand, nine hundred eighty-three".