19205912421 has 6 divisors (see below), whose sum is σ = 27741873510. Its totient is φ = 12803941608.

The previous prime is 19205912417. The next prime is 19205912459. The reversal of 19205912421 is 12421950291.

19205912421 is a `hidden beast` number, since 1 + 9 + 20 + 591 + 2 + 42 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 9780221025 + 9425691396 = 98895^2 + 97086^2 .

It is not a de Polignac number, because 19205912421 - 2² = 19205912417 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19205982421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1066995126 + ... + 1066995143.

It is an arithmetic number, because the mean of its divisors is an integer number (4623645585).

Almost surely, 2^19205912421 is an apocalyptic number.

It is an amenable number.

19205912421 is a deficient number, since it is larger than the sum of its proper divisors (8535961089).

19205912421 is a wasteful number, since it uses less digits than its factorization.

19205912421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2133990275 (or 2133990272 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

It can be divided in two parts, 192059 and 12421, that added together give a triangular number (204480 = T₆₃₉).

The spelling of 19205912421 in words is "nineteen billion, two hundred five million, nine hundred twelve thousand, four hundred twenty-one".