123491281 has 4 divisors (see below), whose sum is σ = 130755492. Its totient is φ = 116227072.

The previous prime is 123491257. The next prime is 123491293. The reversal of 123491281 is 182194321.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 182194321 = 17 ⋅10717313.

It can be written as a sum of positive squares in 2 ways, for example, as 106812225 + 16679056 = 10335^2 + 4084^2 .

It is a cyclic number.

It is not a de Polignac number, because 123491281 - 2²¹ = 121394129 is a prime.

It is a super-2 number, since 2×123491281² = 30500192966041922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (123491201) 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, 3632080 + ... + 3632113.

It is an arithmetic number, because the mean of its divisors is an integer number (32688873).

Almost surely, 2^123491281 is an apocalyptic number.

It is an amenable number.

123491281 is a deficient number, since it is larger than the sum of its proper divisors (7264211).

123491281 is an equidigital number, since it uses as much as digits as its factorization.

123491281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7264210.

The product of its digits is 3456, while the sum is 31.

The square root of 123491281 is about 11112.6630921665. The cubic root of 123491281 is about 497.9802266844.

The spelling of 123491281 in words is "one hundred twenty-three million, four hundred ninety-one thousand, two hundred eighty-one".