18759661 has 2 divisors, whose sum is σ = 18759662. Its totient is φ = 18759660.

The previous prime is 18759649. The next prime is 18759667. The reversal of 18759661 is 16695781.

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., 17892900 + 866761 = 4230^2 + 931^2 .

It is a cyclic number.

It is not a de Polignac number, because 18759661 - 2⁹ = 18759149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18759667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9379830 + 9379831.

It is an arithmetic number, because the mean of its divisors is an integer number (9379831).

Almost surely, 2^18759661 is an apocalyptic number.

It is an amenable number.

18759661 is a deficient number, since it is larger than the sum of its proper divisors (1).

18759661 is an equidigital number, since it uses as much as digits as its factorization.

18759661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 90720, while the sum is 43.

The square root of 18759661 is about 4331.2424314508. The cubic root of 18759661 is about 265.7102626587.

The spelling of 18759661 in words is "eighteen million, seven hundred fifty-nine thousand, six hundred sixty-one".