123256649 has 4 divisors (see below), whose sum is σ = 123558420. Its totient is φ = 122954880.

The previous prime is 123256597. The next prime is 123256691. The reversal of 123256649 is 946652321.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 946652321 = 41 ⋅23089081.

It can be written as a sum of positive squares in 2 ways, for example, as 57760000 + 65496649 = 7600^2 + 8093^2 .

It is a cyclic number.

It is not a de Polignac number, because 123256649 - 2²⁴ = 106479433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (123256849) 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, 150272 + ... + 151089.

It is an arithmetic number, because the mean of its divisors is an integer number (30889605).

Almost surely, 2^123256649 is an apocalyptic number.

It is an amenable number.

123256649 is a deficient number, since it is larger than the sum of its proper divisors (301771).

123256649 is an equidigital number, since it uses as much as digits as its factorization.

123256649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 301770.

The product of its digits is 77760, while the sum is 38.

The square root of 123256649 is about 11102.1011074481. The cubic root of 123256649 is about 497.6646411808.

The spelling of 123256649 in words is "one hundred twenty-three million, two hundred fifty-six thousand, six hundred forty-nine".