7881355729 has 9 divisors (see below), whose sum is σ = 8535498993. Its totient is φ = 7274032272.

The previous prime is 7881355717. The next prime is 7881355747. The reversal of 7881355729 is 9275531887.

The square root of 7881355729 is 88777.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 917787025 + 6963568704 = 30295^2 + 83448^2 .

It is a de Polignac number, because none of the positive numbers 2^k-7881355729 is a prime.

It is a super-2 number, since 2×7881355729² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 7881355729.

It is not an unprimeable number, because it can be changed into a prime (7881355799) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1150687 + ... + 1157515.

It is an arithmetic number, because the mean of its divisors is an integer number (948388777).

Almost surely, 2^7881355729 is an apocalyptic number.

7881355729 is the 88777-th square number.

7881355729 is the 44389-th centered octagonal number.

It is an amenable number.

7881355729 is a deficient number, since it is larger than the sum of its proper divisors (654143264).

7881355729 is an frugal number, since it uses more digits than its factorization.

7881355729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13684 (or 6842 counting only the distinct ones).

The product of its digits is 4233600, while the sum is 55.

The cubic root of 7881355729 is about 1990.0636940801.

The spelling of 7881355729 in words is "seven billion, eight hundred eighty-one million, three hundred fifty-five thousand, seven hundred twenty-nine".