1720661260361 has 8 divisors (see below), whose sum is σ = 1786328915400.
Its totient is φ = 1655415905920.
The previous prime is 1720661260309. The next prime is 1720661260379. The reversal of 1720661260361 is 1630621660271.
It can be written as a sum of positive squares in 4 ways, for example, as 296541237136 + 1424120023225 = 544556^2 + 1193365^2
It is a sphenic number, since it is the product of 3 distinct primes.
It is a cyclic number.
It is not a de Polignac number, because 1720661260361 - 210 = 1720661259337 is a prime.
It is a Duffinian number.
It is not an unprimeable number, because it can be changed into a prime (1720661200361) by changing a digit.
It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 105566846 + ... + 105583143.
It is an arithmetic number, because the mean of its divisors is an integer number (223291114425).
Almost surely, 21720661260361 is an apocalyptic number.
It is an amenable number.
1720661260361 is a deficient number, since it is larger than the sum of its proper divisors (65667655039).
1720661260361 is a wasteful number, since it uses less digits than its factorization.
1720661260361 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 211150299.
The product of its (nonzero) digits is 108864, while the sum is 41.
The spelling of 1720661260361 in words is "one trillion, seven hundred twenty billion, six hundred sixty-one million, two hundred sixty thousand, three hundred sixty-one".