19806621696 has 117 divisors (see below), whose sum is σ = 57290303109. Its totient is φ = 6593200128.

The previous prime is 19806621691. The next prime is 19806621721. The reversal of 19806621696 is 69612660891.

It is a happy number.

The square root of 19806621696 is 140736.

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

19806621696 is a `hidden beast` number, since 1 + 9 + 8 + 0 + 6 + 621 + 6 + 9 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 19376640000 + 429981696 = 139200^2 + 20736^2 .

It is not an unprimeable number, because it can be changed into a prime (19806621691) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 27020946 + ... + 27021678.

Almost surely, 2^19806621696 is an apocalyptic number.

19806621696 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

19806621696 is the 140736-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19806621696

19806621696 is an abundant number, since it is smaller than the sum of its proper divisors (37483681413).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19806621696 is an frugal number, since it uses more digits than its factorization.

19806621696 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1496 (or 738 counting only the distinct ones).

The product of its (nonzero) digits is 1679616, while the sum is 54.

The spelling of 19806621696 in words is "nineteen billion, eight hundred six million, six hundred twenty-one thousand, six hundred ninety-six".