1239673661 has 2 divisors, whose sum is σ = 1239673662. Its totient is φ = 1239673660.

The previous prime is 1239673649. The next prime is 1239673667. The reversal of 1239673661 is 1663769321.

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., 1156408036 + 83265625 = 34006^2 + 9125^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1239673661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1239673667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 619836830 + 619836831.

It is an arithmetic number, because the mean of its divisors is an integer number (619836831).

Almost surely, 2^1239673661 is an apocalyptic number.

It is an amenable number.

1239673661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1239673661 is an equidigital number, since it uses as much as digits as its factorization.

1239673661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 244944, while the sum is 44.

The square root of 1239673661 is about 35208.9997159817. Note that the first 3 decimals coincide. The cubic root of 1239673661 is about 1074.2428159228.

The spelling of 1239673661 in words is "one billion, two hundred thirty-nine million, six hundred seventy-three thousand, six hundred sixty-one".