123361872571921 has 9 divisors (see below), whose sum is σ = 125733971705979. Its totient is φ = 121033712514936.

The previous prime is 123361872571909. The next prime is 123361872571991. The reversal of 123361872571921 is 129175278163321.

It is a happy number.

The square root of 123361872571921 is 11106839.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 88931218212225 + 34430654359696 = 9430335^2 + 5867764^2 .

It is not a de Polignac number, because 123361872571921 - 2²⁷ = 123361738354193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (123361872571991) 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 8 ways as a sum of consecutive naturals, for example, 588557686 + ... + 588767248.

Almost surely, 2^{123361872571921} is an apocalyptic number.

123361872571921 is the 11106839-th square number.

123361872571921 is the 5553420-th centered octagonal number.

It is an amenable number.

123361872571921 is a deficient number, since it is larger than the sum of its proper divisors (2372099134058).

123361872571921 is an frugal number, since it uses more digits than its factorization.

123361872571921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 419232 (or 209616 counting only the distinct ones).

The product of its digits is 7620480, while the sum is 58.

The spelling of 123361872571921 in words is "one hundred twenty-three trillion, three hundred sixty-one billion, eight hundred seventy-two million, five hundred seventy-one thousand, nine hundred twenty-one".