19910338816 has 27 divisors (see below), whose sum is σ = 39747409891. Its totient is φ = 9954040576.

The previous prime is 19910338793. The next prime is 19910338871. The reversal of 19910338816 is 61883301991.

The square root of 19910338816 is 141104.

It is a perfect power (a square), and thus also a powerful number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 19910338816.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 2253255 + ... + 2262073.

Almost surely, 2^19910338816 is an apocalyptic number.

19910338816 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

19910338816 is the 141104-th square number.

It is an amenable number.

19910338816 is a deficient number, since it is larger than the sum of its proper divisors (19837071075).

19910338816 is an frugal number, since it uses more digits than its factorization.

19910338816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17654 (or 8821 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 49.

Multiplying 19910338816 by its sum of digits (49), we get a square (975606601984 = 987728²).

The spelling of 19910338816 in words is "nineteen billion, nine hundred ten million, three hundred thirty-eight thousand, eight hundred sixteen".