213538181 has 4 divisors (see below), whose sum is σ = 215219712. Its totient is φ = 211856652.

The previous prime is 213538163. The next prime is 213538217. The reversal of 213538181 is 181835312.

213538181 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, 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 213538181 - 2²² = 209343877 is a prime.

It is a super-3 number, since 3×213538181³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213538111) 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, 840575 + ... + 840828.

It is an arithmetic number, because the mean of its divisors is an integer number (53804928).

Almost surely, 2^213538181 is an apocalyptic number.

It is an amenable number.

213538181 is a deficient number, since it is larger than the sum of its proper divisors (1681531).

213538181 is a wasteful number, since it uses less digits than its factorization.

213538181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1681530.

The product of its digits is 5760, while the sum is 32.

The square root of 213538181 is about 14612.9456647180. The cubic root of 213538181 is about 597.7118227977.

The spelling of 213538181 in words is "two hundred thirteen million, five hundred thirty-eight thousand, one hundred eighty-one".