16666813 has 4 divisors (see below), whose sum is σ = 16727260. Its totient is φ = 16606368.

The previous prime is 16666807. The next prime is 16666823. The reversal of 16666813 is 31866661.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31866661 = 23 ⋅1385507.

It can be written as a sum of positive squares in 2 ways, for example, as 11035684 + 5631129 = 3322^2 + 2373^2 .

It is a cyclic number.

It is not a de Polignac number, because 16666813 - 2²¹ = 14569661 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 (16666823) 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, 29808 + ... + 30361.

It is an arithmetic number, because the mean of its divisors is an integer number (4181815).

Almost surely, 2^16666813 is an apocalyptic number.

It is an amenable number.

16666813 is a deficient number, since it is larger than the sum of its proper divisors (60447).

16666813 is an equidigital number, since it uses as much as digits as its factorization.

16666813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60446.

The product of its digits is 31104, while the sum is 37.

The square root of 16666813 is about 4082.5008266992. The cubic root of 16666813 is about 255.4372250398.

The spelling of 16666813 in words is "sixteen million, six hundred sixty-six thousand, eight hundred thirteen".