169489981 has 2 divisors, whose sum is σ = 169489982. Its totient is φ = 169489980.

The previous prime is 169489979. The next prime is 169490011. The reversal of 169489981 is 189984961.

169489981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 90440100 + 79049881 = 9510^2 + 8891^2 .

It is a cyclic number.

It is not a de Polignac number, because 169489981 - 2¹ = 169489979 is a prime.

It is a super-2 number, since 2×169489981² = 57453707318760722, which contains 22 as substring.

Together with 169489979, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (169489951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84744990 + 84744991.

It is an arithmetic number, because the mean of its divisors is an integer number (84744991).

Almost surely, 2^169489981 is an apocalyptic number.

It is an amenable number.

169489981 is a deficient number, since it is larger than the sum of its proper divisors (1).

169489981 is an equidigital number, since it uses as much as digits as its factorization.

169489981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1119744, while the sum is 55.

The square root of 169489981 is about 13018.8317832285. The cubic root of 169489981 is about 553.4112842795.

The spelling of 169489981 in words is "one hundred sixty-nine million, four hundred eighty-nine thousand, nine hundred eighty-one".