123523809785 has 4 divisors (see below), whose sum is σ = 148228571748. Its totient is φ = 98819047824.

The previous prime is 123523809781. The next prime is 123523809797. The reversal of 123523809785 is 587908325321.

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 48660830464 + 74862979321 = 220592^2 + 273611^2 .

It is a cyclic number.

It is not a de Polignac number, because 123523809785 - 2² = 123523809781 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (123523809781) 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, 12352380974 + ... + 12352380983.

It is an arithmetic number, because the mean of its divisors is an integer number (37057142937).

Almost surely, 2^123523809785 is an apocalyptic number.

It is an amenable number.

123523809785 is a deficient number, since it is larger than the sum of its proper divisors (24704761963).

123523809785 is an equidigital number, since it uses as much as digits as its factorization.

123523809785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24704761962.

The product of its (nonzero) digits is 3628800, while the sum is 53.

The spelling of 123523809785 in words is "one hundred twenty-three billion, five hundred twenty-three million, eight hundred nine thousand, seven hundred eighty-five".