19878462081 has 9 divisors (see below), whose sum is σ = 28713945091. Its totient is φ = 13252026072.

The previous prime is 19878462059. The next prime is 19878462089. The reversal of 19878462081 is 18026487891.

The square root of 19878462081 is 140991.

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

19878462081 is a `hidden beast` number, since 1 + 9 + 8 + 7 + 8 + 4 + 620 + 8 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 9334458225 + 10544003856 = 96615^2 + 102684^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 19878462081 - 2²⁷ = 19744244353 is a prime.

It is a super-2 number, since 2×19878462081² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19878462089) 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, 399475 + ... + 446471.

Almost surely, 2^19878462081 is an apocalyptic number.

19878462081 is the 140991-st square number.

19878462081 is the 70496-th centered octagonal number.

It is an amenable number.

19878462081 is a deficient number, since it is larger than the sum of its proper divisors (8835483010).

19878462081 is an frugal number, since it uses more digits than its factorization.

19878462081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94000 (or 47000 counting only the distinct ones).

The product of its (nonzero) digits is 1548288, while the sum is 54.

The spelling of 19878462081 in words is "nineteen billion, eight hundred seventy-eight million, four hundred sixty-two thousand, eighty-one".