181972205664 has 96 divisors (see below), whose sum is σ = 506525848416. Its totient is φ = 57004646400.

The previous prime is 181972205659. The next prime is 181972205683. The reversal of 181972205664 is 466502279181.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×181972205664² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1022514 + ... + 1187214.

It is an arithmetic number, because the mean of its divisors is an integer number (5276310921).

Almost surely, 2^181972205664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 181972205664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (253262924208).

181972205664 is an abundant number, since it is smaller than the sum of its proper divisors (324553642752).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

181972205664 is a wasteful number, since it uses less digits than its factorization.

181972205664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165408 (or 165400 counting only the distinct ones).

The product of its (nonzero) digits is 1451520, while the sum is 51.

The spelling of 181972205664 in words is "one hundred eighty-one billion, nine hundred seventy-two million, two hundred five thousand, six hundred sixty-four".