19988161 has 2 divisors, whose sum is σ = 19988162. Its totient is φ = 19988160.

The previous prime is 19988153. The next prime is 19988183. The reversal of 19988161 is 16188991.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14107536 + 5880625 = 3756^2 + 2425^2 .

It is a cyclic number.

It is not a de Polignac number, because 19988161 - 2³ = 19988153 is a prime.

It is not a weakly prime, because it can be changed into another prime (19988131) 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, 9994080 + 9994081.

It is an arithmetic number, because the mean of its divisors is an integer number (9994081).

Almost surely, 2^19988161 is an apocalyptic number.

It is an amenable number.

19988161 is a deficient number, since it is larger than the sum of its proper divisors (1).

19988161 is an equidigital number, since it uses as much as digits as its factorization.

19988161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 43.

The square root of 19988161 is about 4470.8121186201. The cubic root of 19988161 is about 271.3881911041.

The spelling of 19988161 in words is "nineteen million, nine hundred eighty-eight thousand, one hundred sixty-one".