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61720 = 2351543
BaseRepresentation
bin1111000100011000
310010122221
433010120
53433340
61153424
7344641
oct170430
9103587
1061720
114240a
122b874
1322129
14186c8
151344a
hexf118

61720 has 16 divisors (see below), whose sum is σ = 138960. Its totient is φ = 24672.

The previous prime is 61717. The next prime is 61723. The reversal of 61720 is 2716.

61720 = 572 + 582 + ... + 712.

It is an interprime number because it is at equal distance from previous prime (61717) and next prime (61723).

It is an Ulam number.

It is a plaindrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 61694 and 61703.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61723) 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 3 ways as a sum of consecutive naturals, for example, 732 + ... + 811.

It is an arithmetic number, because the mean of its divisors is an integer number (8685).

261720 is an apocalyptic number.

It is an amenable number.

61720 is an abundant number, since it is smaller than the sum of its proper divisors (77240).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (69480).

61720 is a wasteful number, since it uses less digits than its factorization.

61720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1554 (or 1550 counting only the distinct ones).

The product of its (nonzero) digits is 84, while the sum is 16.

The square root of 61720 is about 248.4351021897. The cubic root of 61720 is about 39.5192450150.

The spelling of 61720 in words is "sixty-one thousand, seven hundred twenty".

Divisors: 1 2 4 5 8 10 20 40 1543 3086 6172 7715 12344 15430 30860 61720