1995661 has 2 divisors, whose sum is σ = 1995662. Its totient is φ = 1995660.

The previous prime is 1995649. The next prime is 1995677. The reversal of 1995661 is 1665991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1425636 + 570025 = 1194^2 + 755^2 .

It is a cyclic number.

It is not a de Polignac number, because 1995661 - 2⁵ = 1995629 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1995661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1995611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 997830 + 997831.

It is an arithmetic number, because the mean of its divisors is an integer number (997831).

2^1995661 is an apocalyptic number.

It is an amenable number.

1995661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1995661 is an equidigital number, since it uses as much as digits as its factorization.

1995661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14580, while the sum is 37.

The square root of 1995661 is about 1412.6786612673. The cubic root of 1995661 is about 125.9009257293.

The spelling of 1995661 in words is "one million, nine hundred ninety-five thousand, six hundred sixty-one".