20418431 has 4 divisors (see below), whose sum is σ = 22274664. Its totient is φ = 18562200.

The previous prime is 20418427. The next prime is 20418439. The reversal of 20418431 is 13481402.

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 20418431 - 2² = 20418427 is a prime.

It is a super-2 number, since 2×20418431² = 833824649003522, 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 = 20418397 and 20418406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20418439) 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, 928100 + ... + 928121.

It is an arithmetic number, because the mean of its divisors is an integer number (5568666).

Almost surely, 2^20418431 is an apocalyptic number.

20418431 is a deficient number, since it is larger than the sum of its proper divisors (1856233).

20418431 is a wasteful number, since it uses less digits than its factorization.

20418431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1856232.

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 20418431 is about 4518.6758016038. The cubic root of 20418431 is about 273.3217056657.

Adding to 20418431 its reverse (13481402), we get a palindrome (33899833).

The spelling of 20418431 in words is "twenty million, four hundred eighteen thousand, four hundred thirty-one".