20684123 has 4 divisors (see below), whose sum is σ = 20835240. Its totient is φ = 20533008.

The previous prime is 20684117. The next prime is 20684143. The reversal of 20684123 is 32148602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32148602 = 2 ⋅16074301.

It is a cyclic number.

It is not a de Polignac number, because 20684123 - 2¹² = 20680027 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20684092 and 20684101.

It is not an unprimeable number, because it can be changed into a prime (20684143) 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, 75353 + ... + 75626.

It is an arithmetic number, because the mean of its divisors is an integer number (5208810).

Almost surely, 2^20684123 is an apocalyptic number.

20684123 is a deficient number, since it is larger than the sum of its proper divisors (151117).

20684123 is a wasteful number, since it uses less digits than its factorization.

20684123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151116.

The product of its (nonzero) digits is 2304, while the sum is 26.

The square root of 20684123 is about 4547.9801010998. The cubic root of 20684123 is about 274.5021206357.

The spelling of 20684123 in words is "twenty million, six hundred eighty-four thousand, one hundred twenty-three".