158055991 has 4 divisors (see below), whose sum is σ = 158340312. Its totient is φ = 157771672.

The previous prime is 158055967. The next prime is 158056001. The reversal of 158055991 is 199550851.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 199550851 = 101 ⋅1975751.

It is a cyclic number.

It is not a de Polignac number, because 158055991 - 2¹⁷ = 157924919 is a prime.

It is a super-3 number, since 3×158055991³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (158055791) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 141325 + ... + 142438.

It is an arithmetic number, because the mean of its divisors is an integer number (39585078).

Almost surely, 2^158055991 is an apocalyptic number.

158055991 is a deficient number, since it is larger than the sum of its proper divisors (284321).

158055991 is an equidigital number, since it uses as much as digits as its factorization.

158055991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 284320.

The product of its (nonzero) digits is 81000, while the sum is 43.

The square root of 158055991 is about 12572.0320950911. The cubic root of 158055991 is about 540.6758695426.

The spelling of 158055991 in words is "one hundred fifty-eight million, fifty-five thousand, nine hundred ninety-one".