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78021 = 328669
BaseRepresentation
bin10011000011000101
310222000200
4103003011
54444041
61401113
7443316
oct230305
9128020
1078021
1153689
1239199
1329688
142060d
15181b6
hex130c5

78021 has 6 divisors (see below), whose sum is σ = 112710. Its totient is φ = 52008.

The previous prime is 78017. The next prime is 78031. The reversal of 78021 is 12087.

It can be written as a sum of positive squares in only one way, i.e., 65025 + 12996 = 255^2 + 114^2 .

It is not a de Polignac number, because 78021 - 22 = 78017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 77985 and 78003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4326 + ... + 4343.

It is an arithmetic number, because the mean of its divisors is an integer number (18785).

278021 is an apocalyptic number.

It is an amenable number.

78021 is a deficient number, since it is larger than the sum of its proper divisors (34689).

78021 is a wasteful number, since it uses less digits than its factorization.

78021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8675 (or 8672 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The square root of 78021 is about 279.3223943761. The cubic root of 78021 is about 42.7304209102.

The spelling of 78021 in words is "seventy-eight thousand, twenty-one".

Divisors: 1 3 9 8669 26007 78021