166421851 has 2 divisors, whose sum is σ = 166421852. Its totient is φ = 166421850.

The previous prime is 166421839. The next prime is 166421861. The reversal of 166421851 is 158124661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 166421851 - 2¹³ = 166413659 is a prime.

It is not a weakly prime, because it can be changed into another prime (166421821) 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, 83210925 + 83210926.

It is an arithmetic number, because the mean of its divisors is an integer number (83210926).

Almost surely, 2^166421851 is an apocalyptic number.

166421851 is a deficient number, since it is larger than the sum of its proper divisors (1).

166421851 is an equidigital number, since it uses as much as digits as its factorization.

166421851 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11520, while the sum is 34.

The square root of 166421851 is about 12900.4593329075. The cubic root of 166421851 is about 550.0516216011.

The spelling of 166421851 in words is "one hundred sixty-six million, four hundred twenty-one thousand, eight hundred fifty-one".