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81628 = 2220407
BaseRepresentation
bin10011111011011100
311010222021
4103323130
510103003
61425524
7456661
oct237334
9133867
1081628
1156368
123b2a4
132b201
1421a68
15192bd
hex13edc

81628 has 6 divisors (see below), whose sum is σ = 142856. Its totient is φ = 40812.

The previous prime is 81619. The next prime is 81629. The reversal of 81628 is 82618.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81629) by changing a digit.

81628 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 as a sum of consecutive naturals, namely, 10200 + ... + 10207.

281628 is an apocalyptic number.

It is an amenable number.

81628 is a deficient number, since it is larger than the sum of its proper divisors (61228).

81628 is a wasteful number, since it uses less digits than its factorization.

81628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20411 (or 20409 counting only the distinct ones).

The product of its digits is 768, while the sum is 25.

The square root of 81628 is about 285.7061427411. The cubic root of 81628 is about 43.3790182227.

Subtracting 81628 from its reverse (82618), we obtain a triangular number (990 = T44).

The spelling of 81628 in words is "eighty-one thousand, six hundred twenty-eight".

Divisors: 1 2 4 20407 40814 81628