19272978121 has 4 divisors (see below), whose sum is σ = 19588928644. Its totient is φ = 18957027600.

The previous prime is 19272978113. The next prime is 19272978139. The reversal of 19272978121 is 12187927291.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 262083721 + 19010894400 = 16189^2 + 137880^2 .

It is a cyclic number.

It is not a de Polignac number, because 19272978121 - 2³ = 19272978113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19272978521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 157975170 + ... + 157975291.

It is an arithmetic number, because the mean of its divisors is an integer number (4897232161).

Almost surely, 2^19272978121 is an apocalyptic number.

It is an amenable number.

19272978121 is a deficient number, since it is larger than the sum of its proper divisors (315950523).

19272978121 is an equidigital number, since it uses as much as digits as its factorization.

19272978121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 315950522.

The product of its digits is 254016, while the sum is 49.

The spelling of 19272978121 in words is "nineteen billion, two hundred seventy-two million, nine hundred seventy-eight thousand, one hundred twenty-one".