149991 has 12 divisors (see below), whose sum is σ = 213672. Its totient is φ = 93568.

The previous prime is 149971. The next prime is 149993. The reversal of 149991 is 199941.

It is not a de Polignac number, because 149991 - 2¹⁵ = 117223 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (149993) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 781 + ... + 953.

It is an arithmetic number, because the mean of its divisors is an integer number (17806).

2¹⁴⁹⁹⁹¹ is an apocalyptic number.

149991 is a deficient number, since it is larger than the sum of its proper divisors (63681).

149991 is a wasteful number, since it uses less digits than its factorization.

149991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210 (or 193 counting only the distinct ones).

The product of its digits is 2916, while the sum is 33.

The square root of 149991 is about 387.2867154964. The cubic root of 149991 is about 53.1318657793.

The spelling of 149991 in words is "one hundred forty-nine thousand, nine hundred ninety-one".