20681057 has 4 divisors (see below), whose sum is σ = 20696256. Its totient is φ = 20665860.

The previous prime is 20681041. The next prime is 20681069. The reversal of 20681057 is 75018602.

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 20681057 - 2⁴ = 20681041 is a prime.

It is a super-2 number, since 2×20681057² = 855412237274498, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20681957) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5333 + ... + 8354.

It is an arithmetic number, because the mean of its divisors is an integer number (5174064).

Almost surely, 2^20681057 is an apocalyptic number.

It is an amenable number.

20681057 is a deficient number, since it is larger than the sum of its proper divisors (15199).

20681057 is a wasteful number, since it uses less digits than its factorization.

20681057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15198.

The product of its (nonzero) digits is 3360, while the sum is 29.

The square root of 20681057 is about 4547.6430158930. The cubic root of 20681057 is about 274.4885568491.

Adding to 20681057 its reverse (75018602), we get a palindrome (95699659).

It can be divided in two parts, 2068 and 1057, that added together give a 5-th power (3125 = 5⁵).

The spelling of 20681057 in words is "twenty million, six hundred eighty-one thousand, fifty-seven".