7655040221 has 2 divisors, whose sum is σ = 7655040222. Its totient is φ = 7655040220.

The previous prime is 7655040209. The next prime is 7655040229. The reversal of 7655040221 is 1220405567.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6778228900 + 876811321 = 82330^2 + 29611^2 .

It is an emirp because it is prime and its reverse (1220405567) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7655040221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7655040229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3827520110 + 3827520111.

It is an arithmetic number, because the mean of its divisors is an integer number (3827520111).

Almost surely, 2^7655040221 is an apocalyptic number.

It is an amenable number.

7655040221 is a deficient number, since it is larger than the sum of its proper divisors (1).

7655040221 is an equidigital number, since it uses as much as digits as its factorization.

7655040221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16800, while the sum is 32.

The square root of 7655040221 is about 87493.0867040362. The cubic root of 7655040221 is about 1970.8299749435.

Adding to 7655040221 its reverse (1220405567), we get a palindrome (8875445788).

The spelling of 7655040221 in words is "seven billion, six hundred fifty-five million, forty thousand, two hundred twenty-one".