19646821449 has 6 divisors (see below), whose sum is σ = 28378742106. Its totient is φ = 13097880960.

The previous prime is 19646821433. The next prime is 19646821451. The reversal of 19646821449 is 94412864691.

19646821449 is a `hidden beast` number, since 196 + 4 + 6 + 8 + 2 + 1 + 449 = 666.

It can be written as a sum of positive squares in only one way, i.e., 10871815824 + 8775005625 = 104268^2 + 93675^2 .

It is not a de Polignac number, because 19646821449 - 2⁴ = 19646821433 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19646821395 and 19646821404.

It is not an unprimeable number, because it can be changed into a prime (19646821949) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1091490072 + ... + 1091490089.

It is an arithmetic number, because the mean of its divisors is an integer number (4729790351).

Almost surely, 2^19646821449 is an apocalyptic number.

It is an amenable number.

19646821449 is a deficient number, since it is larger than the sum of its proper divisors (8731920657).

19646821449 is a wasteful number, since it uses less digits than its factorization.

19646821449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2182980167 (or 2182980164 counting only the distinct ones).

The product of its digits is 2985984, while the sum is 54.

The spelling of 19646821449 in words is "nineteen billion, six hundred forty-six million, eight hundred twenty-one thousand, four hundred forty-nine".