158991631 has 2 divisors, whose sum is σ = 158991632. Its totient is φ = 158991630.

The previous prime is 158991611. The next prime is 158991689. The reversal of 158991631 is 136199851.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 158991631 - 2¹¹ = 158989583 is a prime.

It is a super-2 number, since 2×158991631² = 50556677456080322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (158991611) 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 as a sum of consecutive naturals, namely, 79495815 + 79495816.

It is an arithmetic number, because the mean of its divisors is an integer number (79495816).

Almost surely, 2^158991631 is an apocalyptic number.

158991631 is a deficient number, since it is larger than the sum of its proper divisors (1).

158991631 is an equidigital number, since it uses as much as digits as its factorization.

158991631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 58320, while the sum is 43.

The square root of 158991631 is about 12609.1883561156. The cubic root of 158991631 is about 541.7406462848.

The spelling of 158991631 in words is "one hundred fifty-eight million, nine hundred ninety-one thousand, six hundred thirty-one".