178494989 has 2 divisors, whose sum is σ = 178494990. Its totient is φ = 178494988.

The previous prime is 178494959. The next prime is 178494991. The reversal of 178494989 is 989494871.

178494989 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 115562500 + 62932489 = 10750^2 + 7933^2 .

It is an emirp because it is prime and its reverse (989494871) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-178494989 is a prime.

It is a super-2 number, since 2×178494989² = 63720922196220242, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 178494991, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (178494959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 89247494 + 89247495.

It is an arithmetic number, because the mean of its divisors is an integer number (89247495).

Almost surely, 2^178494989 is an apocalyptic number.

It is an amenable number.

178494989 is a deficient number, since it is larger than the sum of its proper divisors (1).

178494989 is an equidigital number, since it uses as much as digits as its factorization.

178494989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5225472, while the sum is 59.

The square root of 178494989 is about 13360.2016826094. The cubic root of 178494989 is about 563.0435781758.

The spelling of 178494989 in words is "one hundred seventy-eight million, four hundred ninety-four thousand, nine hundred eighty-nine".