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21104309 = 42150129
BaseRepresentation
bin101000010000…
…0011010110101
31110201012200002
41100200122311
520400314214
62032201045
7344245412
oct120403265
943635602
1021104309
1110a04a86
127099185
1344abc75
142b35109
151cbd1de
hex14206b5

21104309 has 4 divisors (see below), whose sum is σ = 21154860. Its totient is φ = 21053760.

The previous prime is 21104287. The next prime is 21104311. The reversal of 21104309 is 90340112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9394225 + 11710084 = 3065^2 + 3422^2 .

It is a cyclic number.

It is not a de Polignac number, because 21104309 - 224 = 4327093 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21104329) 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, 24644 + ... + 25485.

It is an arithmetic number, because the mean of its divisors is an integer number (5288715).

Almost surely, 221104309 is an apocalyptic number.

It is an amenable number.

21104309 is a deficient number, since it is larger than the sum of its proper divisors (50551).

21104309 is an equidigital number, since it uses as much as digits as its factorization.

21104309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50550.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 21104309 is about 4593.9426422192. The cubic root of 21104309 is about 276.3484580421.

The spelling of 21104309 in words is "twenty-one million, one hundred four thousand, three hundred nine".

Divisors: 1 421 50129 21104309