123256138945 has 4 divisors (see below), whose sum is σ = 147907366740. Its totient is φ = 98604911152.

The previous prime is 123256138939. The next prime is 123256138969. The reversal of 123256138945 is 549831652321.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13185469584 + 110070669361 = 114828^2 + 331769^2 .

It is a cyclic number.

It is not a de Polignac number, because 123256138945 - 2²¹ = 123254041793 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12325613890 + ... + 12325613899.

It is an arithmetic number, because the mean of its divisors is an integer number (36976841685).

Almost surely, 2^123256138945 is an apocalyptic number.

It is an amenable number.

123256138945 is a deficient number, since it is larger than the sum of its proper divisors (24651227795).

123256138945 is an equidigital number, since it uses as much as digits as its factorization.

123256138945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24651227794.

The product of its digits is 1555200, while the sum is 49.

The spelling of 123256138945 in words is "one hundred twenty-three billion, two hundred fifty-six million, one hundred thirty-eight thousand, nine hundred forty-five".