181449971538 has 32 divisors (see below), whose sum is σ = 416727210240. Its totient is φ = 52090900560.

The previous prime is 181449971509. The next prime is 181449971543. The reversal of 181449971538 is 835179944181.

It is a super-2 number, since 2×181449971538² (a number of 23 digits) contains 22 as substring.

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, 72347220 + ... + 72349727.

It is an arithmetic number, because the mean of its divisors is an integer number (13022725320).

Almost surely, 2^181449971538 is an apocalyptic number.

181449971538 is an abundant number, since it is smaller than the sum of its proper divisors (235277238702).

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

181449971538 is a wasteful number, since it uses less digits than its factorization.

181449971538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144696982.

The product of its digits is 8709120, while the sum is 60.

The spelling of 181449971538 in words is "one hundred eighty-one billion, four hundred forty-nine million, nine hundred seventy-one thousand, five hundred thirty-eight".