166251380899 has 2 divisors, whose sum is σ = 166251380900. Its totient is φ = 166251380898.

The previous prime is 166251380843. The next prime is 166251380909. The reversal of 166251380899 is 998083152661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 166251380899 - 2¹¹ = 166251378851 is a prime.

It is a super-5 number, since 5×166251380899⁵ (a number of 57 digits) contains 55555 as substring.

It is not a weakly prime, because it can be changed into another prime (166251300899) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83125690449 + 83125690450.

It is an arithmetic number, because the mean of its divisors is an integer number (83125690450).

Almost surely, 2^166251380899 is an apocalyptic number.

166251380899 is a deficient number, since it is larger than the sum of its proper divisors (1).

166251380899 is an equidigital number, since it uses as much as digits as its factorization.

166251380899 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5598720, while the sum is 58.

The spelling of 166251380899 in words is "one hundred sixty-six billion, two hundred fifty-one million, three hundred eighty thousand, eight hundred ninety-nine".