126240991 has 4 divisors (see below), whose sum is σ = 129176872. Its totient is φ = 123305112.

The previous prime is 126240977. The next prime is 126241007. The reversal of 126240991 is 199042621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 199042621 = 23 ⋅8654027.

It is a cyclic number.

It is not a de Polignac number, because 126240991 - 2⁹ = 126240479 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (126240791) 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, 1467876 + ... + 1467961.

It is an arithmetic number, because the mean of its divisors is an integer number (32294218).

Almost surely, 2^126240991 is an apocalyptic number.

126240991 is a deficient number, since it is larger than the sum of its proper divisors (2935881).

126240991 is an equidigital number, since it uses as much as digits as its factorization.

126240991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2935880.

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 126240991 is about 11235.7016247318. The cubic root of 126240991 is about 501.6492089057.

The spelling of 126240991 in words is "one hundred twenty-six million, two hundred forty thousand, nine hundred ninety-one".