20936491 has 4 divisors (see below), whose sum is σ = 21012352. Its totient is φ = 20860632.

The previous prime is 20936483. The next prime is 20936497. The reversal of 20936491 is 19463902.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20936491 - 2³ = 20936483 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20936497) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 37515 + ... + 38068.

It is an arithmetic number, because the mean of its divisors is an integer number (5253088).

Almost surely, 2^20936491 is an apocalyptic number.

20936491 is a deficient number, since it is larger than the sum of its proper divisors (75861).

20936491 is an equidigital number, since it uses as much as digits as its factorization.

20936491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75860.

The product of its (nonzero) digits is 11664, while the sum is 34.

The square root of 20936491 is about 4575.6410479844. The cubic root of 20936491 is about 275.6140153444.

The spelling of 20936491 in words is "twenty million, nine hundred thirty-six thousand, four hundred ninety-one".