19690816 has 14 divisors (see below), whose sum is σ = 39074090. Its totient is φ = 9845376.

The previous prime is 19690807. The next prime is 19690817. The reversal of 19690816 is 61809691.

It can be written as a sum of positive squares in only one way, i.e., 18524416 + 1166400 = 4304^2 + 1080^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19690817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 153771 + ... + 153898.

Almost surely, 2^19690816 is an apocalyptic number.

19690816 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

19690816 is a deficient number, since it is larger than the sum of its proper divisors (19383274).

19690816 is an equidigital number, since it uses as much as digits as its factorization.

19690816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 307681 (or 307671 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 40.

The square root of 19690816 is about 4437.4334924594. The cubic root of 19690816 is about 270.0357337250.

The spelling of 19690816 in words is "nineteen million, six hundred ninety thousand, eight hundred sixteen".