1389768078221 has 4 divisors (see below), whose sum is σ = 1389771121500. Its totient is φ = 1389765034944.

The previous prime is 1389768078211. The next prime is 1389768078247. The reversal of 1389768078221 is 1228708679831.

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 144769596196 + 1244998482025 = 380486^2 + 1115795^2 .

It is a cyclic number.

It is not a de Polignac number, because 1389768078221 - 2¹⁰ = 1389768077197 is a prime.

It is a super-3 number, since 3×1389768078221³ (a number of 37 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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 (1389768078211) 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, 682316 + ... + 1801413.

It is an arithmetic number, because the mean of its divisors is an integer number (347442780375).

Almost surely, 2^{1389768078221} is an apocalyptic number.

It is an amenable number.

1389768078221 is a deficient number, since it is larger than the sum of its proper divisors (3043279).

1389768078221 is an equidigital number, since it uses as much as digits as its factorization.

1389768078221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3043278.

The product of its (nonzero) digits is 16257024, while the sum is 62.

The spelling of 1389768078221 in words is "one trillion, three hundred eighty-nine billion, seven hundred sixty-eight million, seventy-eight thousand, two hundred twenty-one".