6991221996 has 48 divisors (see below), whose sum is σ = 19773156480. Its totient is φ = 2118551760.

The previous prime is 6991221971. The next prime is 6991222027.

6991221996 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2941246 + ... + 2943621.

It is an arithmetic number, because the mean of its divisors is an integer number (411940760).

Almost surely, 2^6991221996 is an apocalyptic number.

6991221996 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

6991221996 is an abundant number, since it is smaller than the sum of its proper divisors (12781934484).

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

6991221996 is a wasteful number, since it uses less digits than its factorization.

6991221996 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5884891 (or 5884883 counting only the distinct ones).

The product of its digits is 944784, while the sum is 54.

The square root of 6991221996 is about 83613.5275897387. The cubic root of 6991221996 is about 1912.1312427053.

The spelling of 6991221996 in words is "six billion, nine hundred ninety-one million, two hundred twenty-one thousand, nine hundred ninety-six".