811244447221 has 16 divisors (see below), whose sum is σ = 875021244160. Its totient is φ = 747664344000.

The previous prime is 811244447213. The next prime is 811244447263. The reversal of 811244447221 is 122744442118.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 811244447221 - 2³ = 811244447213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (811244447821) 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, 57819235 + ... + 57833263.

It is an arithmetic number, because the mean of its divisors is an integer number (54688827760).

Almost surely, 2^811244447221 is an apocalyptic number.

It is an amenable number.

811244447221 is a deficient number, since it is larger than the sum of its proper divisors (63776796939).

811244447221 is a wasteful number, since it uses less digits than its factorization.

811244447221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20716.

The product of its digits is 114688, while the sum is 40.

Adding to 811244447221 its reverse (122744442118), we get a palindrome (933988889339).

The spelling of 811244447221 in words is "eight hundred eleven billion, two hundred forty-four million, four hundred forty-seven thousand, two hundred twenty-one".