20109431 has 2 divisors, whose sum is σ = 20109432. Its totient is φ = 20109430.

The previous prime is 20109413. The next prime is 20109451. The reversal of 20109431 is 13490102.

Together with previous prime (20109413) it forms an Ormiston pair, because they use the same digits, order apart.

It is an a-pointer prime, because the next prime (20109451) can be obtained adding 20109431 to its sum of digits (20).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20109431 - 2²² = 15915127 is a prime.

It is a super-2 number, since 2×20109431² = 808778430287522, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20109451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10054715 + 10054716.

It is an arithmetic number, because the mean of its divisors is an integer number (10054716).

Almost surely, 2^20109431 is an apocalyptic number.

20109431 is a deficient number, since it is larger than the sum of its proper divisors (1).

20109431 is an equidigital number, since it uses as much as digits as its factorization.

20109431 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 20109431 is about 4484.3540225990. The cubic root of 20109431 is about 271.9359305195.

Adding to 20109431 its reverse (13490102), we get a palindrome (33599533).

The spelling of 20109431 in words is "twenty million, one hundred nine thousand, four hundred thirty-one".