18161779 has 2 divisors, whose sum is σ = 18161780. Its totient is φ = 18161778.

The previous prime is 18161771. The next prime is 18161791. The reversal of 18161779 is 97716181.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18161779 - 2³ = 18161771 is a prime.

It is not a weakly prime, because it can be changed into another prime (18161771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9080889 + 9080890.

It is an arithmetic number, because the mean of its divisors is an integer number (9080890).

Almost surely, 2^18161779 is an apocalyptic number.

18161779 is a deficient number, since it is larger than the sum of its proper divisors (1).

18161779 is an equidigital number, since it uses as much as digits as its factorization.

18161779 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21168, while the sum is 40.

The square root of 18161779 is about 4261.6638769382. The cubic root of 18161779 is about 262.8569487154.

The spelling of 18161779 in words is "eighteen million, one hundred sixty-one thousand, seven hundred seventy-nine".