19920781881 has 243 divisors, whose sum is σ = 40705444143. Its totient is φ = 9349179840.

The previous prime is 19920781843. The next prime is 19920781949. The reversal of 19920781881 is 18818702991.

The square root of 19920781881 is 141141.

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

It can be written as a sum of positive squares in only one way, i.e., 2946861225 + 16973920656 = 54285^2 + 130284^2 .

It is not a de Polignac number, because 19920781881 - 2⁹ = 19920781369 is a prime.

It is a super-2 number, since 2×19920781881² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (19920781081) by changing a digit.

It is a polite number, since it can be written in 242 ways as a sum of consecutive naturals, for example, 423846400 + ... + 423846446.

Almost surely, 2^19920781881 is an apocalyptic number.

19920781881 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

19920781881 is the 141141-st square number.

19920781881 is the 70571-st centered octagonal number.

It is an amenable number.

19920781881 is an abundant number, since it is smaller than the sum of its proper divisors (20784662262).

19920781881 is a wasteful number, since it uses less digits than its factorization.

19920781881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162 (or 81 counting only the distinct ones).

The product of its (nonzero) digits is 580608, while the sum is 54.

The spelling of 19920781881 in words is "nineteen billion, nine hundred twenty million, seven hundred eighty-one thousand, eight hundred eighty-one".