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99821 = 173577
BaseRepresentation
bin11000010111101101
312001221002
4120113231
511143241
62050045
7564011
oct302755
9161832
1099821
1168aa7
1249925
1336587
1428541
151e89b
hex185ed

99821 has 4 divisors (see below), whose sum is σ = 100572. Its totient is φ = 99072.

The previous prime is 99817. The next prime is 99823. The reversal of 99821 is 12899.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 96100 + 3721 = 310^2 + 61^2 .

It is a cyclic number.

It is not a de Polignac number, because 99821 - 22 = 99817 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99823) 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, 116 + ... + 461.

It is an arithmetic number, because the mean of its divisors is an integer number (25143).

299821 is an apocalyptic number.

It is an amenable number.

99821 is a deficient number, since it is larger than the sum of its proper divisors (751).

99821 is a wasteful number, since it uses less digits than its factorization.

99821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 750.

The product of its digits is 1296, while the sum is 29.

The square root of 99821 is about 315.9446153996. The cubic root of 99821 is about 46.3881769817.

The spelling of 99821 in words is "ninety-nine thousand, eight hundred twenty-one".

Divisors: 1 173 577 99821