120405423521 has 4 divisors (see below), whose sum is σ = 120406484100. Its totient is φ = 120404362944.

The previous prime is 120405423497. The next prime is 120405423529. The reversal of 120405423521 is 125324504021.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 125324504021 = 53987 ⋅2321383.

It can be written as a sum of positive squares in 2 ways, for example, as 107036282896 + 13369140625 = 327164^2 + 115625^2 .

It is a cyclic number.

It is not a de Polignac number, because 120405423521 - 2²² = 120401229217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (120405423529) 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, 336356 + ... + 594933.

It is an arithmetic number, because the mean of its divisors is an integer number (30101621025).

Almost surely, 2^120405423521 is an apocalyptic number.

It is an amenable number.

120405423521 is a deficient number, since it is larger than the sum of its proper divisors (1060579).

120405423521 is an equidigital number, since it uses as much as digits as its factorization.

120405423521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1060578.

The product of its (nonzero) digits is 9600, while the sum is 29.

Adding to 120405423521 its reverse (125324504021), we get a palindrome (245729927542).

The spelling of 120405423521 in words is "one hundred twenty billion, four hundred five million, four hundred twenty-three thousand, five hundred twenty-one".