20121723 has 8 divisors (see below), whose sum is σ = 29810000. Its totient is φ = 13414464.

The previous prime is 20121719. The next prime is 20121763. The reversal of 20121723 is 32712102.

It is not a de Polignac number, because 20121723 - 2² = 20121719 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20121696 and 20121705.

It is not an unprimeable number, because it can be changed into a prime (20121713) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 372598 + ... + 372651.

It is an arithmetic number, because the mean of its divisors is an integer number (3726250).

Almost surely, 2^20121723 is an apocalyptic number.

20121723 is a deficient number, since it is larger than the sum of its proper divisors (9688277).

20121723 is an equidigital number, since it uses as much as digits as its factorization.

20121723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 745258 (or 745252 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 20121723 is about 4485.7243562216. The cubic root of 20121723 is about 271.9913266770.

Adding to 20121723 its reverse (32712102), we get a palindrome (52833825).

The spelling of 20121723 in words is "twenty million, one hundred twenty-one thousand, seven hundred twenty-three".