20781159 has 8 divisors (see below), whose sum is σ = 31666560. Its totient is φ = 11874936.

The previous prime is 20781149. The next prime is 20781181. The reversal of 20781159 is 95118702.

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

It is not a de Polignac number, because 20781159 - 2⁷ = 20781031 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20781149) 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 7 ways as a sum of consecutive naturals, for example, 494769 + ... + 494810.

It is an arithmetic number, because the mean of its divisors is an integer number (3958320).

Almost surely, 2^20781159 is an apocalyptic number.

20781159 is a deficient number, since it is larger than the sum of its proper divisors (10885401).

20781159 is an equidigital number, since it uses as much as digits as its factorization.

20781159 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 989589.

The product of its (nonzero) digits is 5040, while the sum is 33.

The square root of 20781159 is about 4558.6356511570. The cubic root of 20781159 is about 274.9307109180.

The spelling of 20781159 in words is "twenty million, seven hundred eighty-one thousand, one hundred fifty-nine".