18461389 has 2 divisors, whose sum is σ = 18461390. Its totient is φ = 18461388.

The previous prime is 18461363. The next prime is 18461393. The reversal of 18461389 is 98316481.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15468489 + 2992900 = 3933^2 + 1730^2 .

It is an emirp because it is prime and its reverse (98316481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18461389 - 2⁹ = 18460877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18461309) 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, 9230694 + 9230695.

It is an arithmetic number, because the mean of its divisors is an integer number (9230695).

Almost surely, 2^18461389 is an apocalyptic number.

It is an amenable number.

18461389 is a deficient number, since it is larger than the sum of its proper divisors (1).

18461389 is an equidigital number, since it uses as much as digits as its factorization.

18461389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 41472, while the sum is 40.

The square root of 18461389 is about 4296.6718515614. The cubic root of 18461389 is about 264.2944993706.

The spelling of 18461389 in words is "eighteen million, four hundred sixty-one thousand, three hundred eighty-nine".