20418331 has 4 divisors (see below), whose sum is σ = 21493000. Its totient is φ = 19343664.

The previous prime is 20418311. The next prime is 20418337. The reversal of 20418331 is 13381402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13381402 = 2 ⋅6690701.

It is a cyclic number.

It is not a de Polignac number, because 20418331 - 2¹³ = 20410139 is a prime.

It is a super-2 number, since 2×20418331² = 833816481651122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20418337) 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, 537306 + ... + 537343.

It is an arithmetic number, because the mean of its divisors is an integer number (5373250).

Almost surely, 2^20418331 is an apocalyptic number.

20418331 is a deficient number, since it is larger than the sum of its proper divisors (1074669).

20418331 is a wasteful number, since it uses less digits than its factorization.

20418331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1074668.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 20418331 is about 4518.6647364017. The cubic root of 20418331 is about 273.3212594640.

Adding to 20418331 its reverse (13381402), we get a palindrome (33799733).

The spelling of 20418331 in words is "twenty million, four hundred eighteen thousand, three hundred thirty-one".