1980191 has 2 divisors, whose sum is σ = 1980192. Its totient is φ = 1980190.

The previous prime is 1980169. The next prime is 1980221. The reversal of 1980191 is 1910891.

It is a weak prime.

It is an emirp because it is prime and its reverse (1910891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1980191 - 2¹⁴ = 1963807 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1980101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 990095 + 990096.

It is an arithmetic number, because the mean of its divisors is an integer number (990096).

2^1980191 is an apocalyptic number.

1980191 is a deficient number, since it is larger than the sum of its proper divisors (1).

1980191 is an equidigital number, since it uses as much as digits as its factorization.

1980191 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 29.

The square root of 1980191 is about 1407.1925952051. The cubic root of 1980191 is about 125.5747611464.

The spelling of 1980191 in words is "one million, nine hundred eighty thousand, one hundred ninety-one".