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21497 = 73783
BaseRepresentation
bin101001111111001
31002111012
411033321
51141442
6243305
7116450
oct51771
932435
1021497
1115173
1210535
139a28
147b97
156582
hex53f9

21497 has 8 divisors (see below), whose sum is σ = 25536. Its totient is φ = 17712.

The previous prime is 21493. The next prime is 21499. The reversal of 21497 is 79412.

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

It is a cyclic number.

It is not a de Polignac number, because 21497 - 22 = 21493 is a prime.

It is a d-powerful number, because it can be written as 29 + 1 + 46 + 92 + 75 .

It is not an unprimeable number, because it can be changed into a prime (21491) 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, 218 + ... + 300.

It is an arithmetic number, because the mean of its divisors is an integer number (3192).

221497 is an apocalyptic number.

It is an amenable number.

21497 is a deficient number, since it is larger than the sum of its proper divisors (4039).

21497 is an equidigital number, since it uses as much as digits as its factorization.

21497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127.

The product of its digits is 504, while the sum is 23.

The square root of 21497 is about 146.6185527142. The cubic root of 21497 is about 27.8051954474.

The spelling of 21497 in words is "twenty-one thousand, four hundred ninety-seven".

Divisors: 1 7 37 83 259 581 3071 21497