1278796843921 has 9 divisors (see below), whose sum is σ = 1287493700283. Its totient is φ = 1270158364800.

The previous prime is 1278796843799. The next prime is 1278796843927. The reversal of 1278796843921 is 1293486978721.

The square root of 1278796843921 is 1130839.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 643141445521 + 635655398400 = 801961^2 + 797280^2 .

It is not a de Polignac number, because 1278796843921 - 2¹⁷ = 1278796712849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1278796843927) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 170752945 + ... + 170760433.

It is an arithmetic number, because the mean of its divisors is an integer number (143054855587).

Almost surely, 2^{1278796843921} is an apocalyptic number.

1278796843921 is the 1130839-th square number.

1278796843921 is the 565420-th centered octagonal number.

It is an amenable number.

1278796843921 is a deficient number, since it is larger than the sum of its proper divisors (8696856362).

1278796843921 is an frugal number, since it uses more digits than its factorization.

1278796843921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15280 (or 7640 counting only the distinct ones).

The product of its digits is 73156608, while the sum is 67.

The spelling of 1278796843921 in words is "one trillion, two hundred seventy-eight billion, seven hundred ninety-six million, eight hundred forty-three thousand, nine hundred twenty-one".