7621386991 has 2 divisors, whose sum is σ = 7621386992. Its totient is φ = 7621386990.

The previous prime is 7621386923. The next prime is 7621387003. The reversal of 7621386991 is 1996831267.

It is a happy number.

7621386991 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is an emirp because it is prime and its reverse (1996831267) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7621386991 - 2¹¹ = 7621384943 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7621386391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3810693495 + 3810693496.

It is an arithmetic number, because the mean of its divisors is an integer number (3810693496).

Almost surely, 2^7621386991 is an apocalyptic number.

7621386991 is a deficient number, since it is larger than the sum of its proper divisors (1).

7621386991 is an equidigital number, since it uses as much as digits as its factorization.

7621386991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 979776, while the sum is 52.

The square root of 7621386991 is about 87300.5555022418. Note that the first 4 decimals coincide. The cubic root of 7621386991 is about 1967.9376659392.

It can be divided in two parts, 762138 and 6991, that added together give a square (769129 = 877²).

The spelling of 7621386991 in words is "seven billion, six hundred twenty-one million, three hundred eighty-six thousand, nine hundred ninety-one".