7871221787 has 16 divisors (see below), whose sum is σ = 9337106688. Its totient is φ = 6541080480.

The previous prime is 7871221781. The next prime is 7871221843.

7871221787 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 7871221787 - 2⁶ = 7871221723 is a prime.

It is a super-2 number, since 2×7871221787² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (7871221781) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 252473 + ... + 281930.

It is an arithmetic number, because the mean of its divisors is an integer number (583569168).

Almost surely, 2^7871221787 is an apocalyptic number.

7871221787 is a deficient number, since it is larger than the sum of its proper divisors (1465884901).

7871221787 is a wasteful number, since it uses less digits than its factorization.

7871221787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 534530.

The product of its digits is 614656, while the sum is 50.

The square root of 7871221787 is about 88719.9063739362. The cubic root of 7871221787 is about 1989.2103789626.

The spelling of 7871221787 in words is "seven billion, eight hundred seventy-one million, two hundred twenty-one thousand, seven hundred eighty-seven".