218149321 has 8 divisors (see below), whose sum is σ = 248749704. Its totient is φ = 189523200.

The previous prime is 218149303. The next prime is 218149333. The reversal of 218149321 is 123941812.

It can be written as a sum of positive squares in 4 ways, for example, as 42719296 + 175430025 = 6536^2 + 13245^2 .

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 218149321 - 2⁵ = 218149289 is a prime.

It is a super-2 number, since 2×218149321² = 95178252505522082, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (218149361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 493330 + ... + 493771.

It is an arithmetic number, because the mean of its divisors is an integer number (31093713).

Almost surely, 2^218149321 is an apocalyptic number.

It is an amenable number.

218149321 is a deficient number, since it is larger than the sum of its proper divisors (30600383).

218149321 is a wasteful number, since it uses less digits than its factorization.

218149321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 987131.

The product of its digits is 3456, while the sum is 31.

The square root of 218149321 is about 14769.8788417509. The cubic root of 218149321 is about 601.9835473773.

The spelling of 218149321 in words is "two hundred eighteen million, one hundred forty-nine thousand, three hundred twenty-one".