20975891 has 8 divisors (see below), whose sum is σ = 21375120. Its totient is φ = 20579328.

The previous prime is 20975881. The next prime is 20975923. The reversal of 20975891 is 19857902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20975891 - 2⁶ = 20975827 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20975821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22115 + ... + 23043.

It is an arithmetic number, because the mean of its divisors is an integer number (2671890).

Almost surely, 2^20975891 is an apocalyptic number.

20975891 is a deficient number, since it is larger than the sum of its proper divisors (399229).

20975891 is an equidigital number, since it uses as much as digits as its factorization.

20975891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1333.

The product of its (nonzero) digits is 45360, while the sum is 41.

The square root of 20975891 is about 4579.9444319773. The cubic root of 20975891 is about 275.7867979979.

The spelling of 20975891 in words is "twenty million, nine hundred seventy-five thousand, eight hundred ninety-one".