7720 has 16 divisors (see below), whose sum is σ = 17460. Its totient is φ = 3072.

The previous prime is 7717. The next prime is 7723. The reversal of 7720 is 277.

Adding to 7720 its reverse (277), we get a palindrome (7997).

It can be divided in two parts, 77 and 20, that multiplied together give a triangular number (1540 = T_{55}).

It is an interprime number because it is at equal distance from previous prime (7717) and next prime (7723).

It can be written as a sum of positive squares in 2 ways, for example, as 7396 + 324 = 86^2 + 18^2 .

It is a plaindrome in base 11, base 13 and base 15.

It is a nialpdrome in base 10.

It is a junction number, because it is equal to *n*+sod(*n*) for *n* = 7694 and 7703.

It is not an unprimeable number, because it can be changed into a prime (7723) 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, 57 + ... + 136.

It is an amenable number.

7720 is an abundant number, since it is smaller than the sum of its proper divisors (9740).

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 (8730).

7720 is a wasteful number, since it uses less digits than its factorization.

7720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 204 (or 200 counting only the distinct ones).

The product of its (nonzero) digits is 98, while the sum is 16.

The square root of 7720 is about 87.8635305460. The cubic root of 7720 is about 19.7638902447.

The spelling of 7720 in words is "seven thousand, seven hundred twenty", and thus it is an iban number.

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