181681656 has 64 divisors (see below), whose sum is σ = 492391200. Its totient is φ = 55531008.

The previous prime is 181681651. The next prime is 181681691. The reversal of 181681656 is 656186181.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181681651) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47130 + ... + 50838.

Almost surely, 2^181681656 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 181681656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (246195600).

181681656 is an abundant number, since it is smaller than the sum of its proper divisors (310709544).

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

181681656 is a wasteful number, since it uses less digits than its factorization.

181681656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3888 (or 3884 counting only the distinct ones).

The product of its digits is 69120, while the sum is 42.

The square root of 181681656 is about 13478.9337857265. The cubic root of 181681656 is about 566.3745019084.

The spelling of 181681656 in words is "one hundred eighty-one million, six hundred eighty-one thousand, six hundred fifty-six".