16665493 has 4 divisors (see below), whose sum is σ = 17947468. Its totient is φ = 15383520.

The previous prime is 16665469. The next prime is 16665497. The reversal of 16665493 is 39456661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 39456661 = 23 ⋅1715507.

It can be written as a sum of positive squares in 2 ways, for example, as 3755844 + 12909649 = 1938^2 + 3593^2 .

It is a cyclic number.

It is not a de Polignac number, because 16665493 - 2⁵ = 16665461 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16665497) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 640968 + ... + 640993.

It is an arithmetic number, because the mean of its divisors is an integer number (4486867).

Almost surely, 2^16665493 is an apocalyptic number.

16665493 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

16665493 is a deficient number, since it is larger than the sum of its proper divisors (1281975).

16665493 is a wasteful number, since it uses less digits than its factorization.

16665493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1281974.

The product of its digits is 116640, while the sum is 40.

The square root of 16665493 is about 4082.3391578849. The cubic root of 16665493 is about 255.4304813782.

The spelling of 16665493 in words is "sixteen million, six hundred sixty-five thousand, four hundred ninety-three".