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18213831 = 325934301
BaseRepresentation
bin100010101111…
…0101111000111
31021021100200100
41011132233013
514130320311
61450215143
7310546356
oct105365707
937240610
1018213831
11a310359
1261244b3
133a0941c
1425c199d
1518eba56
hex115ebc7

18213831 has 12 divisors (see below), whose sum is σ = 26755560. Its totient is φ = 11936400.

The previous prime is 18213829. The next prime is 18213857. The reversal of 18213831 is 13831281.

It is not a de Polignac number, because 18213831 - 21 = 18213829 is a prime.

It is a super-2 number, since 2×182138312 = 663487279393122, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 18213795 and 18213804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18213931) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16620 + ... + 17681.

It is an arithmetic number, because the mean of its divisors is an integer number (2229630).

Almost surely, 218213831 is an apocalyptic number.

18213831 is a deficient number, since it is larger than the sum of its proper divisors (8541729).

18213831 is a wasteful number, since it uses less digits than its factorization.

18213831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34366 (or 34363 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 18213831 is about 4267.7665118889. The cubic root of 18213831 is about 263.1078268460.

It can be divided in two parts, 18213 and 831, that added together give a square (19044 = 1382).

The spelling of 18213831 in words is "eighteen million, two hundred thirteen thousand, eight hundred thirty-one".

Divisors: 1 3 9 59 177 531 34301 102903 308709 2023759 6071277 18213831