194870989 has 2 divisors, whose sum is σ = 194870990. Its totient is φ = 194870988.

The previous prime is 194870987. The next prime is 194870999. The reversal of 194870989 is 989078491.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 193682889 + 1188100 = 13917^2 + 1090^2 .

It is a cyclic number.

It is not a de Polignac number, because 194870989 - 2¹ = 194870987 is a prime.

Together with 194870987, 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 (194870987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97435494 + 97435495.

It is an arithmetic number, because the mean of its divisors is an integer number (97435495).

Almost surely, 2^194870989 is an apocalyptic number.

It is an amenable number.

194870989 is a deficient number, since it is larger than the sum of its proper divisors (1).

194870989 is an equidigital number, since it uses as much as digits as its factorization.

194870989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1306368, while the sum is 55.

The square root of 194870989 is about 13959.6199446833. The cubic root of 194870989 is about 579.7610876893.

The spelling of 194870989 in words is "one hundred ninety-four million, eight hundred seventy thousand, nine hundred eighty-nine".