20123311 has 4 divisors (see below), whose sum is σ = 21671272. Its totient is φ = 18575352.

The previous prime is 20123293. The next prime is 20123339. The reversal of 20123311 is 11332102.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11332102 = 2 ⋅5666051.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20123311 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13), and also a Moran number because the ratio is a prime number: 1547947 = 20123311 / (2 + 0 + 1 + 2 + 3 + 3 + 1 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20123291 and 20123300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20123381) 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, 773961 + ... + 773986.

It is an arithmetic number, because the mean of its divisors is an integer number (5417818).

Almost surely, 2^20123311 is an apocalyptic number.

20123311 is a deficient number, since it is larger than the sum of its proper divisors (1547961).

20123311 is a wasteful number, since it uses less digits than its factorization.

20123311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1547960.

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 20123311 is about 4485.9013587015. The cubic root of 20123311 is about 271.9984816452.

Adding to 20123311 its reverse (11332102), we get a palindrome (31455413).

The spelling of 20123311 in words is "twenty million, one hundred twenty-three thousand, three hundred eleven".