6987665543321 has 4 divisors (see below), whose sum is σ = 6996281654544. Its totient is φ = 6979049432100.

The previous prime is 6987665543317. The next prime is 6987665543329. The reversal of 6987665543321 is 1233455667896.

It is a happy number.

6987665543321 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 6987665543321 - 2² = 6987665543317 is a prime.

It is a super-2 number, since 2×6987665543321² (a number of 26 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (6987665543329) 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, 4308054395 + ... + 4308056016.

It is an arithmetic number, because the mean of its divisors is an integer number (1749070413636).

Almost surely, 2^{6987665543321} is an apocalyptic number.

It is an amenable number.

6987665543321 is a deficient number, since it is larger than the sum of its proper divisors (8616111223).

6987665543321 is an equidigital number, since it uses as much as digits as its factorization.

6987665543321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8616111222.

The product of its digits is 195955200, while the sum is 65.

The spelling of 6987665543321 in words is "six trillion, nine hundred eighty-seven billion, six hundred sixty-five million, five hundred forty-three thousand, three hundred twenty-one".