18992161 has 2 divisors, whose sum is σ = 18992162. Its totient is φ = 18992160.

The previous prime is 18992123. The next prime is 18992209. The reversal of 18992161 is 16129981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18147600 + 844561 = 4260^2 + 919^2 .

It is a cyclic number.

It is not a de Polignac number, because 18992161 - 2⁷ = 18992033 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18992161.

It is not a weakly prime, because it can be changed into another prime (18992261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9496080 + 9496081.

It is an arithmetic number, because the mean of its divisors is an integer number (9496081).

Almost surely, 2^18992161 is an apocalyptic number.

It is an amenable number.

18992161 is a deficient number, since it is larger than the sum of its proper divisors (1).

18992161 is an equidigital number, since it uses as much as digits as its factorization.

18992161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7776, while the sum is 37.

The square root of 18992161 is about 4357.9996558054. Note that the first 3 decimals coincide. The cubic root of 18992161 is about 266.8034622794.

The spelling of 18992161 in words is "eighteen million, nine hundred ninety-two thousand, one hundred sixty-one".