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28081031 = 1119134359
BaseRepresentation
bin110101100011…
…1101110000111
31221211122221012
41223013232013
524142043111
62441512435
7460453616
oct153075607
957748835
1028081031
111493a770
1294a271b
135a826c4
143a2d87d
1526ea48b
hex1ac7b87

28081031 has 8 divisors (see below), whose sum is σ = 32246400. Its totient is φ = 24184440.

The previous prime is 28081007. The next prime is 28081033. The reversal of 28081031 is 13018082.

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 28081031 - 26 = 28080967 is a prime.

It is a super-2 number, since 2×280810312 = 1577088604045922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28080988 and 28081006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28081033) 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, 66971 + ... + 67388.

It is an arithmetic number, because the mean of its divisors is an integer number (4030800).

Almost surely, 228081031 is an apocalyptic number.

28081031 is a deficient number, since it is larger than the sum of its proper divisors (4165369).

28081031 is a wasteful number, since it uses less digits than its factorization.

28081031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134389.

The product of its (nonzero) digits is 384, while the sum is 23.

The square root of 28081031 is about 5299.1538003723. The cubic root of 28081031 is about 303.9515410697.

The spelling of 28081031 in words is "twenty-eight million, eighty-one thousand, thirty-one".

Divisors: 1 11 19 209 134359 1477949 2552821 28081031