20123123513 has 4 divisors (see below), whose sum is σ = 20157058548. Its totient is φ = 20089188480.

The previous prime is 20123123483. The next prime is 20123123543. The reversal of 20123123513 is 31532132102.

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

It is an interprime number because it is at equal distance from previous prime (20123123483) and next prime (20123123543).

It can be written as a sum of positive squares in 2 ways, for example, as 8491069609 + 11632053904 = 92147^2 + 107852^2 .

It is a cyclic number.

It is not a de Polignac number, because 20123123513 - 2¹⁰ = 20123122489 is a prime.

It is a super-2 number, since 2×20123123513² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20123123543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16966628 + ... + 16967813.

It is an arithmetic number, because the mean of its divisors is an integer number (5039264637).

Almost surely, 2^20123123513 is an apocalyptic number.

It is an amenable number.

20123123513 is a deficient number, since it is larger than the sum of its proper divisors (33935035).

20123123513 is an equidigital number, since it uses as much as digits as its factorization.

20123123513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33935034.

The product of its (nonzero) digits is 1080, while the sum is 23.

Adding to 20123123513 its reverse (31532132102), we get a palindrome (51655255615).

The spelling of 20123123513 in words is "twenty billion, one hundred twenty-three million, one hundred twenty-three thousand, five hundred thirteen".