218614981 has 8 divisors (see below), whose sum is σ = 241795064. Its totient is φ = 196344000.

The previous prime is 218614943. The next prime is 218614997. The reversal of 218614981 is 189416812.

218614981 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 4 ways, for example, as 111492481 + 107122500 = 10559^2 + 10350^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 218614981 - 2⁹ = 218614469 is a prime.

It is a super-2 number, since 2×218614981² = 95585019835260722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218614901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 226770 + ... + 227731.

It is an arithmetic number, because the mean of its divisors is an integer number (30224383).

Almost surely, 2^218614981 is an apocalyptic number.

It is an amenable number.

218614981 is a deficient number, since it is larger than the sum of its proper divisors (23180083).

218614981 is a wasteful number, since it uses less digits than its factorization.

218614981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 454551.

The product of its digits is 27648, while the sum is 40.

The square root of 218614981 is about 14785.6342779064. The cubic root of 218614981 is about 602.4115729111.

The spelling of 218614981 in words is "two hundred eighteen million, six hundred fourteen thousand, nine hundred eighty-one".