40020191 has 2 divisors, whose sum is σ = 40020192. Its totient is φ = 40020190.

The previous prime is 40020187. The next prime is 40020221. The reversal of 40020191 is 19102004.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 40020191 - 2² = 40020187 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40020131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20010095 + 20010096.

It is an arithmetic number, because the mean of its divisors is an integer number (20010096).

Almost surely, 2^40020191 is an apocalyptic number.

40020191 is a deficient number, since it is larger than the sum of its proper divisors (1).

40020191 is an equidigital number, since it uses as much as digits as its factorization.

40020191 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 40020191 is about 6326.1513576581. The cubic root of 40020191 is about 342.0527231964.

Adding to 40020191 its reverse (19102004), we get a palindrome (59122195).

The spelling of 40020191 in words is "forty million, twenty thousand, one hundred ninety-one".