126991 has 6 divisors (see below), whose sum is σ = 132392. Its totient is φ = 121800.

The previous prime is 126989. The next prime is 127031. The reversal of 126991 is 199621.

It is not a de Polignac number, because 126991 - 2¹ = 126989 is a prime.

It is a super-2 number, since 2×126991² = 32253428162, which contains 22 as substring.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (126961) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 766 + ... + 916.

2¹²⁶⁹⁹¹ is an apocalyptic number.

126991 is a deficient number, since it is larger than the sum of its proper divisors (5401).

126991 is an equidigital number, since it uses as much as digits as its factorization.

126991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 209 (or 180 counting only the distinct ones).

The product of its digits is 972, while the sum is 28.

The square root of 126991 is about 356.3579660959. The cubic root of 126991 is about 50.2640695568.

The spelling of 126991 in words is "one hundred twenty-six thousand, nine hundred ninety-one".