218523031 has 4 divisors (see below), whose sum is σ = 218672064. Its totient is φ = 218374000.

The previous prime is 218522963. The next prime is 218523037. The reversal of 218523031 is 130325812.

218523031 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 218523031 - 2²³ = 210134423 is a prime.

It is a super-2 number, since 2×218523031² = 95504630154853922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 218522987 and 218523005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218523037) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72295 + ... + 75256.

It is an arithmetic number, because the mean of its divisors is an integer number (54668016).

Almost surely, 2^218523031 is an apocalyptic number.

218523031 is a deficient number, since it is larger than the sum of its proper divisors (149033).

218523031 is a wasteful number, since it uses less digits than its factorization.

218523031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149032.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 218523031 is about 14782.5245137629. The cubic root of 218523031 is about 602.3271024696.

Adding to 218523031 its reverse (130325812), we get a palindrome (348848843).

The spelling of 218523031 in words is "two hundred eighteen million, five hundred twenty-three thousand, thirty-one".