19966406 has 4 divisors (see below), whose sum is σ = 29949612. Its totient is φ = 9983202.

The previous prime is 19966403. The next prime is 19966411. The reversal of 19966406 is 60466991.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19966403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4991600 + ... + 4991603.

It is an arithmetic number, because the mean of its divisors is an integer number (7487403).

Almost surely, 2^19966406 is an apocalyptic number.

19966406 is a deficient number, since it is larger than the sum of its proper divisors (9983206).

19966406 is an equidigital number, since it uses as much as digits as its factorization.

19966406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9983205.

The product of its (nonzero) digits is 69984, while the sum is 41.

The square root of 19966406 is about 4468.3784530856. The cubic root of 19966406 is about 271.2896962439.

The spelling of 19966406 in words is "nineteen million, nine hundred sixty-six thousand, four hundred six".