1319720761681 has 9 divisors (see below), whose sum is σ = 1535194730331. Its totient is φ = 1131182331552.

The previous prime is 1319720761643. The next prime is 1319720761699. The reversal of 1319720761681 is 1861670279131.

The square root of 1319720761681 is 1148791.

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., 818762571025 + 500958190656 = 904855^2 + 707784^2 .

It is not a de Polignac number, because 1319720761681 - 2⁹ = 1319720761169 is a prime.

It is a super-2 number, since 2×1319720761681² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1319720761621) 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, 7959481 + ... + 8123593.

It is an arithmetic number, because the mean of its divisors is an integer number (170577192259).

Almost surely, 2^{1319720761681} is an apocalyptic number.

1319720761681 is the 1148791-st square number.

1319720761681 is the 574396-th centered octagonal number.

It is an amenable number.

1319720761681 is a deficient number, since it is larger than the sum of its proper divisors (215473968650).

1319720761681 is an frugal number, since it uses more digits than its factorization.

1319720761681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328240 (or 164120 counting only the distinct ones).

The product of its (nonzero) digits is 762048, while the sum is 52.

The spelling of 1319720761681 in words is "one trillion, three hundred nineteen billion, seven hundred twenty million, seven hundred sixty-one thousand, six hundred eighty-one".