150991 has 2 divisors, whose sum is σ = 150992. Its totient is φ = 150990.

The previous prime is 150989. The next prime is 151007. The reversal of 150991 is 199051.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 150991 - 2¹ = 150989 is a prime.

Together with 150989, it forms a pair of twin primes.

It is an Ulam number.

150991 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (150901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 75495 + 75496.

It is an arithmetic number, because the mean of its divisors is an integer number (75496).

2¹⁵⁰⁹⁹¹ is an apocalyptic number.

150991 is a deficient number, since it is larger than the sum of its proper divisors (1).

150991 is an equidigital number, since it uses as much as digits as its factorization.

150991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 405, while the sum is 25.

The square root of 150991 is about 388.5756039692. The cubic root of 150991 is about 53.2496822334.

It can be divided in two parts, 1509 and 91, that added together give a square (1600 = 40²).

The spelling of 150991 in words is "one hundred fifty thousand, nine hundred ninety-one".