1205747471021 has 4 divisors (see below), whose sum is σ = 1205749714812. Its totient is φ = 1205745227232.

The previous prime is 1205747471011. The next prime is 1205747471077. The reversal of 1205747471021 is 1201747475021.

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 565675468996 + 640072002025 = 752114^2 + 800045^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1205747471021 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1205747471021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1205747471011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 215945 + ... + 1567841.

It is an arithmetic number, because the mean of its divisors is an integer number (301437428703).

Almost surely, 2^{1205747471021} is an apocalyptic number.

It is an amenable number.

1205747471021 is a deficient number, since it is larger than the sum of its proper divisors (2243791).

1205747471021 is an equidigital number, since it uses as much as digits as its factorization.

1205747471021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2243790.

The product of its (nonzero) digits is 109760, while the sum is 41.

The spelling of 1205747471021 in words is "one trillion, two hundred five billion, seven hundred forty-seven million, four hundred seventy-one thousand, twenty-one".