20040191 has 2 divisors, whose sum is σ = 20040192. Its totient is φ = 20040190.

The previous prime is 20040187. The next prime is 20040197. The reversal of 20040191 is 19104002.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20040191 - 2² = 20040187 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20040197) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10020095 + 10020096.

It is an arithmetic number, because the mean of its divisors is an integer number (10020096).

Almost surely, 2^20040191 is an apocalyptic number.

20040191 is a deficient number, since it is larger than the sum of its proper divisors (1).

20040191 is an equidigital number, since it uses as much as digits as its factorization.

20040191 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 20040191 is about 4476.6271901958. The cubic root of 20040191 is about 271.6234652637.

Adding to 20040191 its reverse (19104002), we get a palindrome (39144193).

The spelling of 20040191 in words is "twenty million, forty thousand, one hundred ninety-one".