1985561 has 2 divisors, whose sum is σ = 1985562. Its totient is φ = 1985560.

The previous prime is 1985551. The next prime is 1985573. The reversal of 1985561 is 1655891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1907161 + 78400 = 1381^2 + 280^2 .

It is an emirp because it is prime and its reverse (1655891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1985561 - 2¹⁰ = 1984537 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1985551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 992780 + 992781.

It is an arithmetic number, because the mean of its divisors is an integer number (992781).

2^1985561 is an apocalyptic number.

It is an amenable number.

1985561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1985561 is an equidigital number, since it uses as much as digits as its factorization.

1985561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10800, while the sum is 35.

The square root of 1985561 is about 1409.0993577459. The cubic root of 1985561 is about 125.6881723974.

The spelling of 1985561 in words is "one million, nine hundred eighty-five thousand, five hundred sixty-one".