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10000021 = 97103093
BaseRepresentation
bin100110001001…
…011010010101
3200211001110011
4212021122111
510030000041
6554200221
7150666403
oct46113225
920731404
1010000021
115710189
123423071
1320c1895
141484473
15d27e81
hex989695

10000021 has 4 divisors (see below), whose sum is σ = 10103212. Its totient is φ = 9896832.

The previous prime is 10000019. The next prime is 10000079. The reversal of 10000021 is 12000001.

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 4774225 + 5225796 = 2185^2 + 2286^2 .

It is a cyclic number.

It is not a de Polignac number, because 10000021 - 21 = 10000019 is a prime.

It is a Duffinian number.

10000021 is a modest number, since divided by 21 gives 10 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10000121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51450 + ... + 51643.

It is an arithmetic number, because the mean of its divisors is an integer number (2525803).

Almost surely, 210000021 is an apocalyptic number.

It is an amenable number.

10000021 is a deficient number, since it is larger than the sum of its proper divisors (103191).

10000021 is an equidigital number, since it uses as much as digits as its factorization.

10000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103190.

The product of its (nonzero) digits is 2, while the sum is 4.

The square root of 10000021 is about 3162.2809805582. The cubic root of 10000021 is about 215.4436198135.

Adding to 10000021 its reverse (12000001), we get a palindrome (22000022).

Multiplying 10000021 by its reverse (12000001), we get a palindrome (120000262000021).

The spelling of 10000021 in words is "ten million, twenty-one", and thus it is an aban number and an uban number.

Divisors: 1 97 103093 10000021