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54781 = 291889
BaseRepresentation
bin1101010111111101
32210010221
431113331
53223111
61101341
7315466
oct152775
983127
1054781
1138181
1227851
131bc1c
1415d6d
1511371
hexd5fd

54781 has 4 divisors (see below), whose sum is σ = 56700. Its totient is φ = 52864.

The previous prime is 54779. The next prime is 54787. The reversal of 54781 is 18745.

54781 = 1652 + 1662.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 27556 + 27225 = 166^2 + 165^2 .

It is a cyclic number.

It is not a de Polignac number, because 54781 - 21 = 54779 is a prime.

It is a super-2 number, since 2×547812 = 6001915922, which contains 22 as substring.

It is an Ulam number.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

54781 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (54787) 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, 916 + ... + 973.

It is an arithmetic number, because the mean of its divisors is an integer number (14175).

254781 is an apocalyptic number.

54781 is the 166-th centered square number.

It is an amenable number.

54781 is a deficient number, since it is larger than the sum of its proper divisors (1919).

54781 is a wasteful number, since it uses less digits than its factorization.

54781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1918.

The product of its digits is 1120, while the sum is 25.

The square root of 54781 is about 234.0534127074. The cubic root of 54781 is about 37.9789819134.

Subtracting from 54781 its sum of digits (25), we obtain a square (54756 = 2342).

The spelling of 54781 in words is "fifty-four thousand, seven hundred eighty-one".

Divisors: 1 29 1889 54781