1868642880721 has 4 divisors (see below), whose sum is σ = 1868739776100. Its totient is φ = 1868545985344.

The previous prime is 1868642880649. The next prime is 1868642880733. The reversal of 1868642880721 is 1270882468681.

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 1489464030096 + 379178850625 = 1220436^2 + 615775^2 .

It is a cyclic number.

It is not a de Polignac number, because 1868642880721 - 2²⁵ = 1868609326289 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 1868642880721.

It is not an unprimeable number, because it can be changed into a prime (1868642880751) 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, 48418756 + ... + 48457333.

It is an arithmetic number, because the mean of its divisors is an integer number (467184944025).

Almost surely, 2^{1868642880721} is an apocalyptic number.

It is an amenable number.

1868642880721 is a deficient number, since it is larger than the sum of its proper divisors (96895379).

1868642880721 is an equidigital number, since it uses as much as digits as its factorization.

1868642880721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96895378.

The product of its (nonzero) digits is 16515072, while the sum is 61.

The spelling of 1868642880721 in words is "one trillion, eight hundred sixty-eight billion, six hundred forty-two million, eight hundred eighty thousand, seven hundred twenty-one".