218123361 has 21 divisors (see below), whose sum is σ = 327634401. Its totient is φ = 145149732.

The previous prime is 218123359. The next prime is 218123369. The reversal of 218123361 is 163321812.

It is a happy number.

The square root of 218123361 is 14769.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 218123361 - 2¹ = 218123359 is a prime.

It is a super-2 number, since 2×218123361² = 95155601227872642, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (218123369) by changing a digit.

It is a polite number, since it can be written in 20 ways as a sum of consecutive naturals, for example, 398490 + ... + 399036.

Almost surely, 2^218123361 is an apocalyptic number.

218123361 is the 14769-th square number.

218123361 is the 7385-th centered octagonal number.

It is an amenable number.

218123361 is a deficient number, since it is larger than the sum of its proper divisors (109511040).

218123361 is an frugal number, since it uses more digits than its factorization.

218123361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1112 (or 550 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The cubic root of 218123361 is about 601.9596675370.

The spelling of 218123361 in words is "two hundred eighteen million, one hundred twenty-three thousand, three hundred sixty-one".