6891221001 has 16 divisors (see below), whose sum is σ = 10757029248. Its totient is φ = 3841795200.

The previous prime is 6891220993. The next prime is 6891221003. The reversal of 6891221001 is 1001221986.

It is a happy number.

It is not a de Polignac number, because 6891221001 - 2³ = 6891220993 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6891221001.

It is not an unprimeable number, because it can be changed into a prime (6891221003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4001010 + ... + 4002731.

It is an arithmetic number, because the mean of its divisors is an integer number (672314328).

Almost surely, 2^6891221001 is an apocalyptic number.

It is an amenable number.

6891221001 is a deficient number, since it is larger than the sum of its proper divisors (3865808247).

6891221001 is a wasteful number, since it uses less digits than its factorization.

6891221001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8003792.

The product of its (nonzero) digits is 1728, while the sum is 30.

The square root of 6891221001 is about 83013.3784458867. The cubic root of 6891221001 is about 1902.9705150709.

Adding to 6891221001 its reverse (1001221986), we get a palindrome (7892442987).

The spelling of 6891221001 in words is "six billion, eight hundred ninety-one million, two hundred twenty-one thousand, one".