18782261 has 2 divisors, whose sum is σ = 18782262. Its totient is φ = 18782260.

The previous prime is 18782251. The next prime is 18782287. The reversal of 18782261 is 16228781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11519236 + 7263025 = 3394^2 + 2695^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18782261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18782201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9391130 + 9391131.

It is an arithmetic number, because the mean of its divisors is an integer number (9391131).

Almost surely, 2^18782261 is an apocalyptic number.

It is an amenable number.

18782261 is a deficient number, since it is larger than the sum of its proper divisors (1).

18782261 is an equidigital number, since it uses as much as digits as its factorization.

18782261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10752, while the sum is 35.

The square root of 18782261 is about 4333.8505973326. The cubic root of 18782261 is about 265.8169213397.

The spelling of 18782261 in words is "eighteen million, seven hundred eighty-two thousand, two hundred sixty-one".