123520516021 has 4 divisors (see below), whose sum is σ = 141166304032. Its totient is φ = 105874728012.

The previous prime is 123520516013. The next prime is 123520516027. The reversal of 123520516021 is 120615025321.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 123520516021 - 2³ = 123520516013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123520516027) 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, 8822893995 + ... + 8822894008.

It is an arithmetic number, because the mean of its divisors is an integer number (35291576008).

Almost surely, 2^123520516021 is an apocalyptic number.

It is an amenable number.

123520516021 is a deficient number, since it is larger than the sum of its proper divisors (17645788011).

123520516021 is an equidigital number, since it uses as much as digits as its factorization.

123520516021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17645788010.

The product of its (nonzero) digits is 3600, while the sum is 28.

The spelling of 123520516021 in words is "one hundred twenty-three billion, five hundred twenty million, five hundred sixteen thousand, twenty-one".