123256987 has 16 divisors (see below), whose sum is σ = 149584320. Its totient is φ = 99145728.

The previous prime is 123256937. The next prime is 123257003. The reversal of 123256987 is 789652321.

It is a cyclic number.

It is not a de Polignac number, because 123256987 - 2¹¹ = 123254939 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (123256927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45939 + ... + 48547.

It is an arithmetic number, because the mean of its divisors is an integer number (9349020).

Almost surely, 2^123256987 is an apocalyptic number.

123256987 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

123256987 is a deficient number, since it is larger than the sum of its proper divisors (26327333).

123256987 is a wasteful number, since it uses less digits than its factorization.

123256987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3030.

The product of its digits is 181440, while the sum is 43.

The square root of 123256987 is about 11102.1163297815. The cubic root of 123256987 is about 497.6650960866.

The spelling of 123256987 in words is "one hundred twenty-three million, two hundred fifty-six thousand, nine hundred eighty-seven".