20840723 has 4 divisors (see below), whose sum is σ = 20889288. Its totient is φ = 20792160.

The previous prime is 20840717. The next prime is 20840761. The reversal of 20840723 is 32704802.

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 20840723 - 2⁴ = 20840707 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20840692 and 20840701.

It is not an unprimeable number, because it can be changed into a prime (20840123) 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, 23633 + ... + 24498.

It is an arithmetic number, because the mean of its divisors is an integer number (5222322).

Almost surely, 2^20840723 is an apocalyptic number.

20840723 is a deficient number, since it is larger than the sum of its proper divisors (48565).

20840723 is an equidigital number, since it uses as much as digits as its factorization.

20840723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48564.

The product of its (nonzero) digits is 2688, while the sum is 26.

The square root of 20840723 is about 4565.1640715313. The cubic root of 20840723 is about 275.1931337510.

The spelling of 20840723 in words is "twenty million, eight hundred forty thousand, seven hundred twenty-three".