159901985 has 4 divisors (see below), whose sum is σ = 191882388. Its totient is φ = 127921584.

The previous prime is 159901981. The next prime is 159902021. The reversal of 159901985 is 589109951.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 35378704 + 124523281 = 5948^2 + 11159^2 .

It is a cyclic number.

It is not a de Polignac number, because 159901985 - 2² = 159901981 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (159901981) 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 in 3 ways as a sum of consecutive naturals, for example, 15990194 + ... + 15990203.

It is an arithmetic number, because the mean of its divisors is an integer number (47970597).

Almost surely, 2^159901985 is an apocalyptic number.

It is an amenable number.

159901985 is a deficient number, since it is larger than the sum of its proper divisors (31980403).

159901985 is an equidigital number, since it uses as much as digits as its factorization.

159901985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31980402.

The product of its (nonzero) digits is 145800, while the sum is 47.

The square root of 159901985 is about 12645.2356640752. The cubic root of 159901985 is about 542.7726449903.

The spelling of 159901985 in words is "one hundred fifty-nine million, nine hundred one thousand, nine hundred eighty-five".