6621550997 has 2 divisors, whose sum is σ = 6621550998. Its totient is φ = 6621550996.

The previous prime is 6621550883. The next prime is 6621551059. The reversal of 6621550997 is 7990551266.

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., 4682117476 + 1939433521 = 68426^2 + 44039^2 .

It is a cyclic number.

It is not a de Polignac number, because 6621550997 - 2²⁶ = 6554442133 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6621550297) 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, 3310775498 + 3310775499.

It is an arithmetic number, because the mean of its divisors is an integer number (3310775499).

Almost surely, 2^6621550997 is an apocalyptic number.

It is an amenable number.

6621550997 is a deficient number, since it is larger than the sum of its proper divisors (1).

6621550997 is an equidigital number, since it uses as much as digits as its factorization.

6621550997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1020600, while the sum is 50.

The square root of 6621550997 is about 81372.9131652542. The cubic root of 6621550997 is about 1877.8168974953.

The spelling of 6621550997 in words is "six billion, six hundred twenty-one million, five hundred fifty thousand, nine hundred ninety-seven".