218181601 has 4 divisors (see below), whose sum is σ = 238016304. Its totient is φ = 198346900.

The previous prime is 218181589. The next prime is 218181653. The reversal of 218181601 is 106181812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 218181601 - 2²³ = 209792993 is a prime.

It is a super-2 number, since 2×218181601² = 95206422029846402, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 218181601.

It is not an unprimeable number, because it can be changed into a prime (218181671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9917335 + ... + 9917356.

It is an arithmetic number, because the mean of its divisors is an integer number (59504076).

Almost surely, 2^218181601 is an apocalyptic number.

It is an amenable number.

218181601 is a deficient number, since it is larger than the sum of its proper divisors (19834703).

218181601 is a wasteful number, since it uses less digits than its factorization.

218181601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19834702.

The product of its (nonzero) digits is 768, while the sum is 28.

The square root of 218181601 is about 14770.9715658788. The cubic root of 218181601 is about 602.0132381573.

The spelling of 218181601 in words is "two hundred eighteen million, one hundred eighty-one thousand, six hundred one".