20409331 has 2 divisors, whose sum is σ = 20409332. Its totient is φ = 20409330.

The previous prime is 20409317. The next prime is 20409353. The reversal of 20409331 is 13390402.

It is an a-pointer prime, because the next prime (20409353) can be obtained adding 20409331 to its sum of digits (22).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20409331 - 2⁷ = 20409203 is a prime.

It is a super-2 number, since 2×20409331² = 833081583735122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20409371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10204665 + 10204666.

It is an arithmetic number, because the mean of its divisors is an integer number (10204666).

Almost surely, 2^20409331 is an apocalyptic number.

20409331 is a deficient number, since it is larger than the sum of its proper divisors (1).

20409331 is an equidigital number, since it uses as much as digits as its factorization.

20409331 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 22.

The square root of 20409331 is about 4517.6687572242. The cubic root of 20409331 is about 273.2810953447.

Adding to 20409331 its reverse (13390402), we get a palindrome (33799733).

The spelling of 20409331 in words is "twenty million, four hundred nine thousand, three hundred thirty-one".