20681023 has 4 divisors (see below), whose sum is σ = 22561128. Its totient is φ = 18800920.

The previous prime is 20681021. The next prime is 20681029. The reversal of 20681023 is 32018602.

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 20681023 - 2¹ = 20681021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20680985 and 20681003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20681021) 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, 940036 + ... + 940057.

It is an arithmetic number, because the mean of its divisors is an integer number (5640282).

Almost surely, 2^20681023 is an apocalyptic number.

20681023 is a deficient number, since it is larger than the sum of its proper divisors (1880105).

20681023 is a wasteful number, since it uses less digits than its factorization.

20681023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1880104.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 20681023 is about 4547.6392776912. The cubic root of 20681023 is about 274.4884064278.

Adding to 20681023 its reverse (32018602), we get a palindrome (52699625).

The spelling of 20681023 in words is "twenty million, six hundred eighty-one thousand, twenty-three".