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90821 is a prime number
BaseRepresentation
bin10110001011000101
311121120202
4112023011
510401241
61540245
7525533
oct261305
9147522
1090821
1162265
1244685
1332453
1425153
151bd9b
hex162c5

90821 has 2 divisors, whose sum is σ = 90822. Its totient is φ = 90820.

The previous prime is 90803. The next prime is 90823. The reversal of 90821 is 12809.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81796 + 9025 = 286^2 + 95^2 .

It is an emirp because it is prime and its reverse (12809) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 90821 - 210 = 89797 is a prime.

It is a super-3 number, since 3×908213 = 2247398533372983, which contains 333 as substring.

Together with 90823, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 90793 and 90802.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45410 + 45411.

It is an arithmetic number, because the mean of its divisors is an integer number (45411).

290821 is an apocalyptic number.

It is an amenable number.

90821 is a deficient number, since it is larger than the sum of its proper divisors (1).

90821 is an equidigital number, since it uses as much as digits as its factorization.

90821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 90821 is about 301.3652269257. The cubic root of 90821 is about 44.9499030973.

It can be divided in two parts, 908 and 21, that added together give a palindrome (929).

The spelling of 90821 in words is "ninety thousand, eight hundred twenty-one".