1720661375137 has 6 divisors (see below), whose sum is σ = 1744554970662. Its totient is φ = 1697090666112.

The previous prime is 1720661375047. The next prime is 1720661375141. The reversal of 1720661375137 is 7315731660271.

It can be written as a sum of positive squares in 3 ways, for example, as 444674251921 + 1275987123216 = 666839^2 + 1129596^2 .

It is not a de Polignac number, because 1720661375137 - 2¹¹ = 1720661373089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1720661375737) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 161437848 + ... + 161448505.

It is an arithmetic number, because the mean of its divisors is an integer number (290759161777).

Almost surely, 2^{1720661375137} is an apocalyptic number.

It is an amenable number.

1720661375137 is a deficient number, since it is larger than the sum of its proper divisors (23893595525).

1720661375137 is an frugal number, since it uses more digits than its factorization.

1720661375137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322886499 (or 322886426 counting only the distinct ones).

The product of its (nonzero) digits is 1111320, while the sum is 49.

The spelling of 1720661375137 in words is "one trillion, seven hundred twenty billion, six hundred sixty-one million, three hundred seventy-five thousand, one hundred thirty-seven".