20681157 has 8 divisors (see below), whose sum is σ = 31514176. Its totient is φ = 11817792.

The previous prime is 20681153. The next prime is 20681159. The reversal of 20681157 is 75118602.

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

It is not a de Polignac number, because 20681157 - 2² = 20681153 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20681153) 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, 492388 + ... + 492429.

It is an arithmetic number, because the mean of its divisors is an integer number (3939272).

Almost surely, 2^20681157 is an apocalyptic number.

It is an amenable number.

20681157 is a deficient number, since it is larger than the sum of its proper divisors (10833019).

20681157 is an equidigital number, since it uses as much as digits as its factorization.

20681157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 984827.

The product of its (nonzero) digits is 3360, while the sum is 30.

The square root of 20681157 is about 4547.6540105861. The cubic root of 20681157 is about 274.4889992639.

Adding to 20681157 its reverse (75118602), we get a palindrome (95799759).

The spelling of 20681157 in words is "twenty million, six hundred eighty-one thousand, one hundred fifty-seven".