181491664 has 10 divisors (see below), whose sum is σ = 351640130. Its totient is φ = 90745824.

The previous prime is 181491659. The next prime is 181491671. The reversal of 181491664 is 466194181.

181491664 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 91393600 + 90098064 = 9560^2 + 9492^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5671599 + ... + 5671630.

It is an arithmetic number, because the mean of its divisors is an integer number (35164013).

Almost surely, 2^181491664 is an apocalyptic number.

It is an amenable number.

181491664 is a deficient number, since it is larger than the sum of its proper divisors (170148466).

181491664 is a wasteful number, since it uses less digits than its factorization.

181491664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11343237 (or 11343231 counting only the distinct ones).

The product of its digits is 41472, while the sum is 40.

The square root of 181491664 is about 13471.8842037779. The cubic root of 181491664 is about 566.1770059915.

The spelling of 181491664 in words is "one hundred eighty-one million, four hundred ninety-one thousand, six hundred sixty-four".