19272987721 has 8 divisors (see below), whose sum is σ = 20830458824. Its totient is φ = 17726221440.

The previous prime is 19272987697. The next prime is 19272987733. The reversal of 19272987721 is 12778927291.

It can be written as a sum of positive squares in 4 ways, for example, as 63027721 + 19209960000 = 7939^2 + 138600^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 19272987721 - 2¹⁷ = 19272856649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19272987821) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2672460 + ... + 2679661.

It is an arithmetic number, because the mean of its divisors is an integer number (2603807353).

Almost surely, 2^19272987721 is an apocalyptic number.

It is an amenable number.

19272987721 is a deficient number, since it is larger than the sum of its proper divisors (1557471103).

19272987721 is a wasteful number, since it uses less digits than its factorization.

19272987721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5352411.

The product of its digits is 1778112, while the sum is 55.

The spelling of 19272987721 in words is "nineteen billion, two hundred seventy-two million, nine hundred eighty-seven thousand, seven hundred twenty-one".