165721720713 has 8 divisors (see below), whose sum is σ = 232591888800. Its totient is φ = 104666349888.

The previous prime is 165721720663. The next prime is 165721720727. The reversal of 165721720713 is 317027127561.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 165721720713 - 2¹² = 165721716617 is a prime.

It is not an unprimeable number, because it can be changed into a prime (165721720763) 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, 1453699248 + ... + 1453699361.

It is an arithmetic number, because the mean of its divisors is an integer number (29073986100).

Almost surely, 2^165721720713 is an apocalyptic number.

It is an amenable number.

165721720713 is a deficient number, since it is larger than the sum of its proper divisors (66870168087).

165721720713 is a wasteful number, since it uses less digits than its factorization.

165721720713 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2907398631.

The product of its (nonzero) digits is 123480, while the sum is 42.

The spelling of 165721720713 in words is "one hundred sixty-five billion, seven hundred twenty-one million, seven hundred twenty thousand, seven hundred thirteen".