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20785813 = 234321017
BaseRepresentation
bin100111101001…
…0101010010101
31110010000202221
41033102222111
520310121223
62021302341
7341451016
oct117225225
943100687
1020785813
1110807764
126b649b1
1343c9cc9
142a9100d
151c58b5d
hex13d2a95

20785813 has 8 divisors (see below), whose sum is σ = 22195008. Its totient is φ = 19418784.

The previous prime is 20785763. The next prime is 20785819. The reversal of 20785813 is 31858702.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2k-20785813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20785819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9520 + ... + 11497.

It is an arithmetic number, because the mean of its divisors is an integer number (2774376).

Almost surely, 220785813 is an apocalyptic number.

20785813 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

20785813 is a deficient number, since it is larger than the sum of its proper divisors (1409195).

20785813 is a wasteful number, since it uses less digits than its factorization.

20785813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21083.

The product of its (nonzero) digits is 13440, while the sum is 34.

The square root of 20785813 is about 4559.1460823273. The cubic root of 20785813 is about 274.9512332258.

The spelling of 20785813 in words is "twenty million, seven hundred eighty-five thousand, eight hundred thirteen".

Divisors: 1 23 43 989 21017 483391 903731 20785813