1664123105551 has 2 divisors, whose sum is σ = 1664123105552. Its totient is φ = 1664123105550.

The previous prime is 1664123105537. The next prime is 1664123105581. The reversal of 1664123105551 is 1555013214661.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1664123105551 - 2⁷ = 1664123105423 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1664123105501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832061552775 + 832061552776.

It is an arithmetic number, because the mean of its divisors is an integer number (832061552776).

Almost surely, 2^{1664123105551} is an apocalyptic number.

1664123105551 is a deficient number, since it is larger than the sum of its proper divisors (1).

1664123105551 is an equidigital number, since it uses as much as digits as its factorization.

1664123105551 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108000, while the sum is 40.

The spelling of 1664123105551 in words is "one trillion, six hundred sixty-four billion, one hundred twenty-three million, one hundred five thousand, five hundred fifty-one".