7768637221 has 2 divisors, whose sum is σ = 7768637222. Its totient is φ = 7768637220.

The previous prime is 7768637167. The next prime is 7768637267. The reversal of 7768637221 is 1227368677.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6290234721 + 1478402500 = 79311^2 + 38450^2 .

It is an emirp because it is prime and its reverse (1227368677) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7768637221 - 2⁹ = 7768636709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7768634221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3884318610 + 3884318611.

It is an arithmetic number, because the mean of its divisors is an integer number (3884318611).

Almost surely, 2^7768637221 is an apocalyptic number.

It is an amenable number.

7768637221 is a deficient number, since it is larger than the sum of its proper divisors (1).

7768637221 is an equidigital number, since it uses as much as digits as its factorization.

7768637221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1185408, while the sum is 49.

The square root of 7768637221 is about 88139.8730484677. The cubic root of 7768637221 is about 1980.5308596816.

The spelling of 7768637221 in words is "seven billion, seven hundred sixty-eight million, six hundred thirty-seven thousand, two hundred twenty-one".