158661805 has 4 divisors (see below), whose sum is σ = 190394172. Its totient is φ = 126929440.

The previous prime is 158661803. The next prime is 158661827. The reversal of 158661805 is 508166851.

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 69189124 + 89472681 = 8318^2 + 9459^2 .

It is not a de Polignac number, because 158661805 - 2¹ = 158661803 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (158661803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15866176 + ... + 15866185.

It is an arithmetic number, because the mean of its divisors is an integer number (47598543).

Almost surely, 2^158661805 is an apocalyptic number.

It is an amenable number.

158661805 is a deficient number, since it is larger than the sum of its proper divisors (31732367).

158661805 is an equidigital number, since it uses as much as digits as its factorization.

158661805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31732366.

The product of its (nonzero) digits is 57600, while the sum is 40.

The square root of 158661805 is about 12596.1027703016. The cubic root of 158661805 is about 541.3657757158.

It can be divided in two parts, 15866 and 1805, that added together give a palindrome (17671).

The spelling of 158661805 in words is "one hundred fifty-eight million, six hundred sixty-one thousand, eight hundred five".