163661389 has 2 divisors, whose sum is σ = 163661390. Its totient is φ = 163661388.

The previous prime is 163661387. The next prime is 163661411. The reversal of 163661389 is 983166361.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 117896164 + 45765225 = 10858^2 + 6765^2 .

It is an emirp because it is prime and its reverse (983166361) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 163661389 - 2¹ = 163661387 is a prime.

Together with 163661387, 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 (163661387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 81830694 + 81830695.

It is an arithmetic number, because the mean of its divisors is an integer number (81830695).

Almost surely, 2^163661389 is an apocalyptic number.

It is an amenable number.

163661389 is a deficient number, since it is larger than the sum of its proper divisors (1).

163661389 is an equidigital number, since it uses as much as digits as its factorization.

163661389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 139968, while the sum is 43.

The square root of 163661389 is about 12793.0211052745. The cubic root of 163661389 is about 546.9933891564.

The spelling of 163661389 in words is "one hundred sixty-three million, six hundred sixty-one thousand, three hundred eighty-nine".