158991689 has 2 divisors, whose sum is σ = 158991690. Its totient is φ = 158991688.

The previous prime is 158991631. The next prime is 158991719. The reversal of 158991689 is 986199851.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 129777664 + 29214025 = 11392^2 + 5405^2 .

It is a cyclic number.

It is not a de Polignac number, because 158991689 - 2¹² = 158987593 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (158991289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 79495844 + 79495845.

It is an arithmetic number, because the mean of its divisors is an integer number (79495845).

Almost surely, 2^158991689 is an apocalyptic number.

It is an amenable number.

158991689 is a deficient number, since it is larger than the sum of its proper divisors (1).

158991689 is an equidigital number, since it uses as much as digits as its factorization.

158991689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1399680, while the sum is 56.

The square root of 158991689 is about 12609.1906560255. The cubic root of 158991689 is about 541.7407121603.

The spelling of 158991689 in words is "one hundred fifty-eight million, nine hundred ninety-one thousand, six hundred eighty-nine".