221608181 has 8 divisors (see below), whose sum is σ = 232508928. Its totient is φ = 210942000.

The previous prime is 221608103. The next prime is 221608199. The reversal of 221608181 is 181806122.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221608181 is a prime.

It is a super-2 number, since 2×221608181² = 98220371772257522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221608081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 56705 + ... + 60486.

It is an arithmetic number, because the mean of its divisors is an integer number (29063616).

Almost surely, 2^221608181 is an apocalyptic number.

It is an amenable number.

221608181 is a deficient number, since it is larger than the sum of its proper divisors (10900747).

221608181 is a wasteful number, since it uses less digits than its factorization.

221608181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117283.

The product of its (nonzero) digits is 1536, while the sum is 29.

The square root of 221608181 is about 14886.5100342558. The cubic root of 221608181 is about 605.1484561578.

The spelling of 221608181 in words is "two hundred twenty-one million, six hundred eight thousand, one hundred eighty-one".