20868641 has 4 divisors (see below), whose sum is σ = 20897472. Its totient is φ = 20839812.

The previous prime is 20868637. The next prime is 20868643. The reversal of 20868641 is 14686802.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20868641 - 2² = 20868637 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20868643) 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 3 ways as a sum of consecutive naturals, for example, 13301 + ... + 14786.

It is an arithmetic number, because the mean of its divisors is an integer number (5224368).

Almost surely, 2^20868641 is an apocalyptic number.

It is an amenable number.

20868641 is a deficient number, since it is larger than the sum of its proper divisors (28831).

20868641 is an equidigital number, since it uses as much as digits as its factorization.

20868641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28830.

The product of its (nonzero) digits is 18432, while the sum is 35.

The square root of 20868641 is about 4568.2207696214. The cubic root of 20868641 is about 275.3159608053.

The spelling of 20868641 in words is "twenty million, eight hundred sixty-eight thousand, six hundred forty-one".