158661809 has 8 divisors (see below), whose sum is σ = 164567208. Its totient is φ = 152841600.

The previous prime is 158661803. The next prime is 158661827. The reversal of 158661809 is 908166851.

It can be written as a sum of positive squares in 4 ways, for example, as 133911184 + 24750625 = 11572^2 + 4975^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 158661809 - 2⁸ = 158661553 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 158661809.

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

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17492 + ... + 24965.

It is an arithmetic number, because the mean of its divisors is an integer number (20570901).

Almost surely, 2^158661809 is an apocalyptic number.

It is an amenable number.

158661809 is a deficient number, since it is larger than the sum of its proper divisors (5905399).

158661809 is a wasteful number, since it uses less digits than its factorization.

158661809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42595.

The product of its (nonzero) digits is 103680, while the sum is 44.

The square root of 158661809 is about 12596.1029290809. The cubic root of 158661809 is about 541.3657802653.

The spelling of 158661809 in words is "one hundred fifty-eight million, six hundred sixty-one thousand, eight hundred nine".