123402122521 has 4 divisors (see below), whose sum is σ = 123405446500. Its totient is φ = 123398798544.

The previous prime is 123402122513. The next prime is 123402122573. The reversal of 123402122521 is 125221204321.

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 52718456025 + 70683666496 = 229605^2 + 265864^2 .

It is a cyclic number.

It is not a de Polignac number, because 123402122521 - 2³ = 123402122513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (123402122321) 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, 1605666 + ... + 1680763.

It is an arithmetic number, because the mean of its divisors is an integer number (30851361625).

Almost surely, 2^123402122521 is an apocalyptic number.

It is an amenable number.

123402122521 is a deficient number, since it is larger than the sum of its proper divisors (3323979).

123402122521 is an equidigital number, since it uses as much as digits as its factorization.

123402122521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3323978.

The product of its (nonzero) digits is 1920, while the sum is 25.

Adding to 123402122521 its reverse (125221204321), we get a palindrome (248623326842).

The spelling of 123402122521 in words is "one hundred twenty-three billion, four hundred two million, one hundred twenty-two thousand, five hundred twenty-one".