16611221251 has 2 divisors, whose sum is σ = 16611221252. Its totient is φ = 16611221250.

The previous prime is 16611221227. The next prime is 16611221281. The reversal of 16611221251 is 15212211661.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 16611221251 - 2⁹ = 16611220739 is a prime.

It is not a weakly prime, because it can be changed into another prime (16611221201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8305610625 + 8305610626.

It is an arithmetic number, because the mean of its divisors is an integer number (8305610626).

Almost surely, 2^16611221251 is an apocalyptic number.

16611221251 is a deficient number, since it is larger than the sum of its proper divisors (1).

16611221251 is an equidigital number, since it uses as much as digits as its factorization.

16611221251 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1440, while the sum is 28.

The spelling of 16611221251 in words is "sixteen billion, six hundred eleven million, two hundred twenty-one thousand, two hundred fifty-one".