166406400 has 324 divisors, whose sum is σ = 622741392. Its totient is φ = 43960320.

The previous prime is 166406381. The next prime is 166406407. The reversal of 166406400 is 4604661.

166406400 is a `hidden beast` number, since 16 + 6 + 4 + 0 + 640 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (324).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (166406407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1555147 + ... + 1555253.

Almost surely, 2^166406400 is an apocalyptic number.

166406400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 166406400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (311370696).

166406400 is an abundant number, since it is smaller than the sum of its proper divisors (456334992).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

166406400 is an equidigital number, since it uses as much as digits as its factorization.

166406400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 148 (or 117 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 166406400 is about 12899.8604643616. The cubic root of 166406400 is about 550.0345983745.

The spelling of 166406400 in words is "one hundred sixty-six million, four hundred six thousand, four hundred".