19918805956 has 81 divisors (see below), whose sum is σ = 43147301799. Its totient is φ = 8020927488.

The previous prime is 19918805917. The next prime is 19918805957. The reversal of 19918805956 is 65950881991.

The square root of 19918805956 is 141134.

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

It can be written as a sum of positive squares in 4 ways, for example, as 3184796356 + 16734009600 = 56434^2 + 129360^2 .

It is a junction number, because it is equal to n+sod(n) for n = 19918805894 and 19918805903.

It is not an unprimeable number, because it can be changed into a prime (19918805957) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 33589596 + ... + 33590188.

Almost surely, 2^19918805956 is an apocalyptic number.

19918805956 is the 141134-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19918805956

19918805956 is an abundant number, since it is smaller than the sum of its proper divisors (23228495843).

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

19918805956 is an equidigital number, since it uses as much as digits as its factorization.

19918805956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1238 (or 619 counting only the distinct ones).

The product of its (nonzero) digits is 6998400, while the sum is 61.

The spelling of 19918805956 in words is "nineteen billion, nine hundred eighteen million, eight hundred five thousand, nine hundred fifty-six".