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813845721 = 31320867839
BaseRepresentation
bin110000100000100…
…100110011011001
32002201101122110010
4300200210303121
53131321030341
6212431312133
726111401023
oct6040446331
92081348403
10813845721
11388438377
121a867b649
13cc7c0020
147a131013
154b6ae716
hex30824cd9

813845721 has 8 divisors (see below), whose sum is σ = 1168599040. Its totient is φ = 500828112.

The previous prime is 813845719. The next prime is 813845737. The reversal of 813845721 is 127548318.

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

It is not a de Polignac number, because 813845721 - 21 = 813845719 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39), and also a Moran number because the ratio is a prime number: 20867839 = 813845721 / (8 + 1 + 3 + 8 + 4 + 5 + 7 + 2 + 1).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 813845721.

It is not an unprimeable number, because it can be changed into a prime (813845701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10433881 + ... + 10433958.

It is an arithmetic number, because the mean of its divisors is an integer number (146074880).

Almost surely, 2813845721 is an apocalyptic number.

It is an amenable number.

813845721 is a deficient number, since it is larger than the sum of its proper divisors (354753319).

813845721 is a wasteful number, since it uses less digits than its factorization.

813845721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20867855.

The product of its digits is 53760, while the sum is 39.

The square root of 813845721 is about 28527.9813691751. The cubic root of 813845721 is about 933.6426761878.

The spelling of 813845721 in words is "eight hundred thirteen million, eight hundred forty-five thousand, seven hundred twenty-one".

Divisors: 1 3 13 39 20867839 62603517 271281907 813845721