18990761 has 2 divisors, whose sum is σ = 18990762. Its totient is φ = 18990760.

The previous prime is 18990721. The next prime is 18990767. The reversal of 18990761 is 16709981.

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., 17682025 + 1308736 = 4205^2 + 1144^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18990761 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (18990767) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9495380 + 9495381.

It is an arithmetic number, because the mean of its divisors is an integer number (9495381).

Almost surely, 2^18990761 is an apocalyptic number.

It is an amenable number.

18990761 is a deficient number, since it is larger than the sum of its proper divisors (1).

18990761 is an equidigital number, since it uses as much as digits as its factorization.

18990761 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27216, while the sum is 41.

The square root of 18990761 is about 4357.8390286930. The cubic root of 18990761 is about 266.7969063460.

The spelling of 18990761 in words is "eighteen million, nine hundred ninety thousand, seven hundred sixty-one".