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13231021 = 43930139
BaseRepresentation
bin110010011110…
…001110101101
3220220012112211
4302132032231
511341343041
61151330421
7220314256
oct62361655
926805484
1013231021
117517731
124520a11
13298340b
141a85b2d
151265481
hexc9e3ad

13231021 has 4 divisors (see below), whose sum is σ = 13261600. Its totient is φ = 13200444.

The previous prime is 13231019. The next prime is 13231027. The reversal of 13231021 is 12013231.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12013231 = 16217411.

It is a cyclic number.

It is not a de Polignac number, because 13231021 - 21 = 13231019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 13230992 and 13231010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13231027) 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, 14631 + ... + 15508.

It is an arithmetic number, because the mean of its divisors is an integer number (3315400).

Almost surely, 213231021 is an apocalyptic number.

It is an amenable number.

13231021 is a deficient number, since it is larger than the sum of its proper divisors (30579).

13231021 is an equidigital number, since it uses as much as digits as its factorization.

13231021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30578.

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 13231021 is about 3637.4470442881. The cubic root of 13231021 is about 236.5181388588.

Adding to 13231021 its reverse (12013231), we get a palindrome (25244252).

The spelling of 13231021 in words is "thirteen million, two hundred thirty-one thousand, twenty-one".

Divisors: 1 439 30139 13231021