1661244997 has 2 divisors, whose sum is σ = 1661244998. Its totient is φ = 1661244996.

The previous prime is 1661244973. The next prime is 1661245009. The reversal of 1661244997 is 7994421661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1153689156 + 507555841 = 33966^2 + 22529^2 .

It is an emirp because it is prime and its reverse (7994421661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1661244997 - 2²⁷ = 1527027269 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1661244997.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1661244197) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830622498 + 830622499.

It is an arithmetic number, because the mean of its divisors is an integer number (830622499).

Almost surely, 2^1661244997 is an apocalyptic number.

It is an amenable number.

1661244997 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661244997 is an equidigital number, since it uses as much as digits as its factorization.

1661244997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 653184, while the sum is 49.

The square root of 1661244997 is about 40758.3733360398. The cubic root of 1661244997 is about 1184.3440848947.

The spelling of 1661244997 in words is "one billion, six hundred sixty-one million, two hundred forty-four thousand, nine hundred ninety-seven".