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20916018 = 23217292357
BaseRepresentation
bin100111111001…
…0011100110010
31110100122101100
41033302130302
520323303033
62024145230
7342532434
oct117623462
943318340
1020916018
1110896572
127008216
134444356
142ac6654
151c82513
hex13f2732

20916018 has 48 divisors (see below), whose sum is σ = 49659480. Its totient is φ = 6332928.

The previous prime is 20915981. The next prime is 20916019. The reversal of 20916018 is 81061902.

It can be written as a sum of positive squares in 4 ways, for example, as 17665209 + 3250809 = 4203^2 + 1803^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20915982 and 20916000.

It is not an unprimeable number, because it can be changed into a prime (20916019) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7696 + ... + 10052.

Almost surely, 220916018 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20916018, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24829740).

20916018 is an abundant number, since it is smaller than the sum of its proper divisors (28743462).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20916018 is a wasteful number, since it uses less digits than its factorization.

20916018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2411 (or 2408 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 20916018 is about 4573.4033279386. The cubic root of 20916018 is about 275.5241485503.

The spelling of 20916018 in words is "twenty million, nine hundred sixteen thousand, eighteen".

Divisors: 1 2 3 6 9 17 18 29 34 51 58 87 102 153 174 261 306 493 522 986 1479 2357 2958 4437 4714 7071 8874 14142 21213 40069 42426 68353 80138 120207 136706 205059 240414 360621 410118 615177 721242 1162001 1230354 2324002 3486003 6972006 10458009 20916018