20423431 has 4 divisors (see below), whose sum is σ = 23341072. Its totient is φ = 17505792.

The previous prime is 20423407. The next prime is 20423441. The reversal of 20423431 is 13432402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13432402 = 2 ⋅6716201.

It is a cyclic number.

It is not a de Polignac number, because 20423431 - 2⁵ = 20423399 is a prime.

It is a super-2 number, since 2×20423431² = 834233067623522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20423399 and 20423408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20423401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1458810 + ... + 1458823.

It is an arithmetic number, because the mean of its divisors is an integer number (5835268).

Almost surely, 2^20423431 is an apocalyptic number.

20423431 is a deficient number, since it is larger than the sum of its proper divisors (2917641).

20423431 is an equidigital number, since it uses as much as digits as its factorization.

20423431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2917640.

The product of its (nonzero) digits is 576, while the sum is 19.

The square root of 20423431 is about 4519.2290271682. The cubic root of 20423431 is about 273.3440138929.

Adding to 20423431 its reverse (13432402), we get a palindrome (33855833).

The spelling of 20423431 in words is "twenty million, four hundred twenty-three thousand, four hundred thirty-one".