12013435661621 has 4 divisors (see below), whose sum is σ = 12040191643500. Its totient is φ = 11986679679744.

The previous prime is 12013435661551. The next prime is 12013435661629. The reversal of 12013435661621 is 12616653431021.

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 6993644702500 + 5019790959121 = 2644550^2 + 2240489^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12013435661621 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12013435661629) 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, 13377990266 + ... + 13377991163.

It is an arithmetic number, because the mean of its divisors is an integer number (3010047910875).

Almost surely, 2^{12013435661621} is an apocalyptic number.

It is an amenable number.

12013435661621 is a deficient number, since it is larger than the sum of its proper divisors (26755981879).

12013435661621 is an equidigital number, since it uses as much as digits as its factorization.

12013435661621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26755981878.

The product of its (nonzero) digits is 155520, while the sum is 41.

The spelling of 12013435661621 in words is "twelve trillion, thirteen billion, four hundred thirty-five million, six hundred sixty-one thousand, six hundred twenty-one".