181720021373 has 8 divisors (see below), whose sum is σ = 203597862240. Its totient is φ = 160735153680.

The previous prime is 181720021367. The next prime is 181720021403. The reversal of 181720021373 is 373120027181.

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 181720021373 - 2¹⁴ = 181720004989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181720021303) 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, 223242863 + ... + 223243676.

It is an arithmetic number, because the mean of its divisors is an integer number (25449732780).

Almost surely, 2^181720021373 is an apocalyptic number.

It is an amenable number.

181720021373 is a deficient number, since it is larger than the sum of its proper divisors (21877840867).

181720021373 is a wasteful number, since it uses less digits than its factorization.

181720021373 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 446486587.

The product of its (nonzero) digits is 14112, while the sum is 35.

The spelling of 181720021373 in words is "one hundred eighty-one billion, seven hundred twenty million, twenty-one thousand, three hundred seventy-three".