1980521 has 2 divisors, whose sum is σ = 1980522. Its totient is φ = 1980520.

The previous prime is 1980491. The next prime is 1980523. The reversal of 1980521 is 1250891.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1690000 + 290521 = 1300^2 + 539^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1980521 is a prime.

Together with 1980523, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1980523) 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, 990260 + 990261.

It is an arithmetic number, because the mean of its divisors is an integer number (990261).

2^1980521 is an apocalyptic number.

It is an amenable number.

1980521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1980521 is an equidigital number, since it uses as much as digits as its factorization.

1980521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 1980521 is about 1407.3098450590. The cubic root of 1980521 is about 125.5817364616.

The spelling of 1980521 in words is "one million, nine hundred eighty thousand, five hundred twenty-one".