20684723 has 4 divisors (see below), whose sum is σ = 20746440. Its totient is φ = 20623008.

The previous prime is 20684717. The next prime is 20684761. The reversal of 20684723 is 32748602.

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 20684723 - 2¹⁸ = 20422579 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20684723.

It is not an unprimeable number, because it can be changed into a prime (20684423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30353 + ... + 31026.

It is an arithmetic number, because the mean of its divisors is an integer number (5186610).

Almost surely, 2^20684723 is an apocalyptic number.

20684723 is a deficient number, since it is larger than the sum of its proper divisors (61717).

20684723 is an equidigital number, since it uses as much as digits as its factorization.

20684723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61716.

The product of its (nonzero) digits is 16128, while the sum is 32.

The square root of 20684723 is about 4548.0460639708. The cubic root of 20684723 is about 274.5047748403.

The spelling of 20684723 in words is "twenty million, six hundred eighty-four thousand, seven hundred twenty-three".