123782321521 has 8 divisors (see below), whose sum is σ = 123984815400. Its totient is φ = 123579980160.

The previous prime is 123782321497. The next prime is 123782321539. The reversal of 123782321521 is 125123287321.

It can be written as a sum of positive squares in 4 ways, for example, as 67691030625 + 56091290896 = 260175^2 + 236836^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 123782321521 - 2¹⁵ = 123782288753 is a prime.

It is a super-2 number, since 2×123782321521² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (123782321591) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1646685 + ... + 1720213.

It is an arithmetic number, because the mean of its divisors is an integer number (15498101925).

Almost surely, 2^123782321521 is an apocalyptic number.

It is an amenable number.

123782321521 is a deficient number, since it is larger than the sum of its proper divisors (202493879).

123782321521 is an equidigital number, since it uses as much as digits as its factorization.

123782321521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76259.

The product of its digits is 40320, while the sum is 37.

The spelling of 123782321521 in words is "one hundred twenty-three billion, seven hundred eighty-two million, three hundred twenty-one thousand, five hundred twenty-one".