166851868690 has 16 divisors (see below), whose sum is σ = 323435930328. Its totient is φ = 61606843776.

The previous prime is 166851868657. The next prime is 166851868691. The reversal of 166851868690 is 96868158661.

It can be written as a sum of positive squares in 4 ways, for example, as 44507918961 + 122343949729 = 210969^2 + 349777^2 .

It is a super-2 number, since 2×166851868690² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (166851868691) 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 in 7 ways as a sum of consecutive naturals, for example, 641737827 + ... + 641738086.

Almost surely, 2^166851868690 is an apocalyptic number.

166851868690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

166851868690 is a deficient number, since it is larger than the sum of its proper divisors (156584061638).

166851868690 is a wasteful number, since it uses less digits than its factorization.

166851868690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1283475933.

The product of its (nonzero) digits is 29859840, while the sum is 64.

The spelling of 166851868690 in words is "one hundred sixty-six billion, eight hundred fifty-one million, eight hundred sixty-eight thousand, six hundred ninety".