7811221 has 8 divisors (see below), whose sum is σ = 8577504. Its totient is φ = 7054320.

The previous prime is 7811203. The next prime is 7811249. The reversal of 7811221 is 1221187.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 7811221 - 2⁵ = 7811189 is a prime.

It is a super-2 number, since 2×7811221² = 122030347021682, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 7811192 and 7811201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7811201) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 535 + ... + 3988.

It is an arithmetic number, because the mean of its divisors is an integer number (1072188).

Almost surely, 2^7811221 is an apocalyptic number.

It is an amenable number.

7811221 is a deficient number, since it is larger than the sum of its proper divisors (766283).

7811221 is a wasteful number, since it uses less digits than its factorization.

7811221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4691.

The product of its digits is 224, while the sum is 22.

The square root of 7811221 is about 2794.8561680344. The cubic root of 7811221 is about 198.4143027134.

It can be divided in two parts, 781 and 1221, that added together give a palindrome (2002).

The spelling of 7811221 in words is "seven million, eight hundred eleven thousand, two hundred twenty-one".