123511312501 has 4 divisors (see below), whose sum is σ = 123512418432. Its totient is φ = 123510206572.

The previous prime is 123511312493. The next prime is 123511312531. The reversal of 123511312501 is 105213115321.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 123511312501 - 2³ = 123511312493 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123511312531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 363895 + ... + 615988.

It is an arithmetic number, because the mean of its divisors is an integer number (30878104608).

Almost surely, 2^123511312501 is an apocalyptic number.

It is an amenable number.

123511312501 is a deficient number, since it is larger than the sum of its proper divisors (1105931).

123511312501 is an equidigital number, since it uses as much as digits as its factorization.

123511312501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1105930.

The product of its (nonzero) digits is 900, while the sum is 25.

Adding to 123511312501 its reverse (105213115321), we get a palindrome (228724427822).

The spelling of 123511312501 in words is "one hundred twenty-three billion, five hundred eleven million, three hundred twelve thousand, five hundred one".