166400649 has 10 divisors (see below), whose sum is σ = 248573930. Its totient is φ = 110933712.

The previous prime is 166400609. The next prime is 166400657. The reversal of 166400649 is 946004661.

166400649 is a `hidden beast` number, since 1 + 6 + 6 + 4 + 0 + 0 + 649 = 666.

It can be written as a sum of positive squares in only one way, i.e., 93605625 + 72795024 = 9675^2 + 8532^2 .

It is not a de Polignac number, because 166400649 - 2¹² = 166396553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166400609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1027084 + ... + 1027245.

It is an arithmetic number, because the mean of its divisors is an integer number (24857393).

Almost surely, 2^166400649 is an apocalyptic number.

It is an amenable number.

166400649 is a deficient number, since it is larger than the sum of its proper divisors (82173281).

166400649 is an equidigital number, since it uses as much as digits as its factorization.

166400649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2054341 (or 2054332 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 166400649 is about 12899.6375530478. The cubic root of 166400649 is about 550.0282619086.

The spelling of 166400649 in words is "one hundred sixty-six million, four hundred thousand, six hundred forty-nine".