7776221 has 8 divisors (see below), whose sum is σ = 7939680. Its totient is φ = 7614288.

The previous prime is 7776211. The next prime is 7776239. The reversal of 7776221 is 1226777.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7776221 is a prime.

It is a super-2 number, since 2×7776221² = 120939226081682, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7776211) 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, 18350 + ... + 18768.

It is an arithmetic number, because the mean of its divisors is an integer number (992460).

Almost surely, 2^7776221 is an apocalyptic number.

It is an amenable number.

7776221 is a deficient number, since it is larger than the sum of its proper divisors (163459).

7776221 is a wasteful number, since it uses less digits than its factorization.

7776221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 763.

The product of its digits is 8232, while the sum is 32.

The square root of 7776221 is about 2788.5876353452. The cubic root of 7776221 is about 198.1175117830.

It can be divided in two parts, 7776 and 221, that added together give a palindrome (7997).

The spelling of 7776221 in words is "seven million, seven hundred seventy-six thousand, two hundred twenty-one".