166399451 has 4 divisors (see below), whose sum is σ = 176187672. Its totient is φ = 156611232.

The previous prime is 166399447. The next prime is 166399469. The reversal of 166399451 is 154993661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 166399451 - 2² = 166399447 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166399421) 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 3 ways as a sum of consecutive naturals, for example, 4894085 + ... + 4894118.

It is an arithmetic number, because the mean of its divisors is an integer number (44046918).

Almost surely, 2^166399451 is an apocalyptic number.

166399451 is a deficient number, since it is larger than the sum of its proper divisors (9788221).

166399451 is an equidigital number, since it uses as much as digits as its factorization.

166399451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9788220.

The product of its digits is 174960, while the sum is 44.

The square root of 166399451 is about 12899.5911175510. The cubic root of 166399451 is about 550.0269419309.

The spelling of 166399451 in words is "one hundred sixty-six million, three hundred ninety-nine thousand, four hundred fifty-one".