21091083 has 16 divisors (see below), whose sum is σ = 31879680. Its totient is φ = 12295584.

The previous prime is 21091079. The next prime is 21091139. The reversal of 21091083 is 38019012.

It is not a de Polignac number, because 21091083 - 2² = 21091079 is a prime.

It is a super-2 number, since 2×21091083² = 889667564225778, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21091003) 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 15 ways as a sum of consecutive naturals, for example, 13491 + ... + 14972.

It is an arithmetic number, because the mean of its divisors is an integer number (1992480).

Almost surely, 2^21091083 is an apocalyptic number.

21091083 is a deficient number, since it is larger than the sum of its proper divisors (10788597).

21091083 is a wasteful number, since it uses less digits than its factorization.

21091083 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28498.

The product of its (nonzero) digits is 432, while the sum is 24.

The square root of 21091083 is about 4592.5029123562. The cubic root of 21091083 is about 276.2907170930.

The spelling of 21091083 in words is "twenty-one million, ninety-one thousand, eighty-three".