661899986327 has 2 divisors, whose sum is σ = 661899986328. Its totient is φ = 661899986326.

The previous prime is 661899986269. The next prime is 661899986347. The reversal of 661899986327 is 723689998166.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 661899986327 - 2²⁸ = 661631550871 is a prime.

It is a super-2 number, since 2×661899986327² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661899986347) 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, 330949993163 + 330949993164.

It is an arithmetic number, because the mean of its divisors is an integer number (330949993164).

Almost surely, 2^661899986327 is an apocalyptic number.

661899986327 is a deficient number, since it is larger than the sum of its proper divisors (1).

661899986327 is an equidigital number, since it uses as much as digits as its factorization.

661899986327 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 423263232, while the sum is 74.

The spelling of 661899986327 in words is "six hundred sixty-one billion, eight hundred ninety-nine million, nine hundred eighty-six thousand, three hundred twenty-seven".