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21140021 = 72431429
BaseRepresentation
bin101000010100…
…1001000110101
31110210000122202
41100221020311
520402440041
62033034245
7344454500
oct120511065
943700582
1021140021
1110a298a1
1270b5985
1344c22b6
142b44137
151cc8a9b
hex1429235

21140021 has 6 divisors (see below), whose sum is σ = 24591510. Its totient is φ = 18119976.

The previous prime is 21140011. The next prime is 21140033. The reversal of 21140021 is 12004112.

It can be written as a sum of positive squares in only one way, i.e., 19140625 + 1999396 = 4375^2 + 1414^2 .

It is not a de Polignac number, because 21140021 - 26 = 21139957 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21139984 and 21140011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21140011) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 215666 + ... + 215763.

It is an arithmetic number, because the mean of its divisors is an integer number (4098585).

Almost surely, 221140021 is an apocalyptic number.

It is an amenable number.

21140021 is a deficient number, since it is larger than the sum of its proper divisors (3451489).

21140021 is an equidigital number, since it uses as much as digits as its factorization.

21140021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431443 (or 431436 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 21140021 is about 4597.8278567167. The cubic root of 21140021 is about 276.5042460492.

Adding to 21140021 its reverse (12004112), we get a palindrome (33144133).

The spelling of 21140021 in words is "twenty-one million, one hundred forty thousand, twenty-one".

Divisors: 1 7 49 431429 3020003 21140021