18523861 has 2 divisors, whose sum is σ = 18523862. Its totient is φ = 18523860.

The previous prime is 18523853. The next prime is 18523877. The reversal of 18523861 is 16832581.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17098225 + 1425636 = 4135^2 + 1194^2 .

It is a cyclic number.

It is not a de Polignac number, because 18523861 - 2³ = 18523853 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18523891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9261930 + 9261931.

It is an arithmetic number, because the mean of its divisors is an integer number (9261931).

Almost surely, 2^18523861 is an apocalyptic number.

It is an amenable number.

18523861 is a deficient number, since it is larger than the sum of its proper divisors (1).

18523861 is an equidigital number, since it uses as much as digits as its factorization.

18523861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11520, while the sum is 34.

The square root of 18523861 is about 4303.9355246100. The cubic root of 18523861 is about 264.5922815306.

The spelling of 18523861 in words is "eighteen million, five hundred twenty-three thousand, eight hundred sixty-one".