142991 has 4 divisors (see below), whose sum is σ = 149232. Its totient is φ = 136752.

The previous prime is 142981. The next prime is 142993. The reversal of 142991 is 199241.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 199241 = 7 ⋅28463.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-142991 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 142991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (142993) 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, 3086 + ... + 3131.

It is an arithmetic number, because the mean of its divisors is an integer number (37308).

2¹⁴²⁹⁹¹ is an apocalyptic number.

142991 is a deficient number, since it is larger than the sum of its proper divisors (6241).

142991 is an equidigital number, since it uses as much as digits as its factorization.

142991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6240.

The product of its digits is 648, while the sum is 26.

The square root of 142991 is about 378.1415079041. The cubic root of 142991 is about 52.2921182341.

The spelling of 142991 in words is "one hundred forty-two thousand, nine hundred ninety-one".