19919966 has 8 divisors (see below), whose sum is σ = 32596344. Its totient is φ = 9054520.

The previous prime is 19919957. The next prime is 19919969. The reversal of 19919966 is 66991991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19919969) 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, 452705 + ... + 452748.

It is an arithmetic number, because the mean of its divisors is an integer number (4074543).

Almost surely, 2^19919966 is an apocalyptic number.

19919966 is a deficient number, since it is larger than the sum of its proper divisors (12676378).

19919966 is a wasteful number, since it uses less digits than its factorization.

19919966 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 905466.

The product of its digits is 236196, while the sum is 50.

The square root of 19919966 is about 4463.1789119416. The cubic root of 19919966 is about 271.0792014436.

The spelling of 19919966 in words is "nineteen million, nine hundred nineteen thousand, nine hundred sixty-six".