166405401 has 32 divisors (see below), whose sum is σ = 274780800. Its totient is φ = 98910720.

The previous prime is 166405397. The next prime is 166405409. The reversal of 166405401 is 104504661.

166405401 is a `hidden beast` number, since 16 + 640 + 5 + 4 + 0 + 1 = 666.

166405401 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 166405401 - 2² = 166405397 is a prime.

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 (166405409) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 820 + ... + 18261.

It is an arithmetic number, because the mean of its divisors is an integer number (8586900).

Almost surely, 2^166405401 is an apocalyptic number.

It is an amenable number.

166405401 is a deficient number, since it is larger than the sum of its proper divisors (108375399).

166405401 is a wasteful number, since it uses less digits than its factorization.

166405401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19126 (or 19120 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 166405401 is about 12899.8217429544. The cubic root of 166405401 is about 550.0334976843.

The spelling of 166405401 in words is "one hundred sixty-six million, four hundred five thousand, four hundred one".