1980491 has 2 divisors, whose sum is σ = 1980492. Its totient is φ = 1980490.

The previous prime is 1980469. The next prime is 1980521. The reversal of 1980491 is 1940891.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1980491 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1980401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 990245 + 990246.

It is an arithmetic number, because the mean of its divisors is an integer number (990246).

2^1980491 is an apocalyptic number.

1980491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1980491 is an equidigital number, since it uses as much as digits as its factorization.

1980491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 1980491 is about 1407.2991863850. The cubic root of 1980491 is about 125.5811023741.

The spelling of 1980491 in words is "one million, nine hundred eighty thousand, four hundred ninety-one".