19328901821 has 4 divisors (see below), whose sum is σ = 19593681372. Its totient is φ = 19064122272.

The previous prime is 19328901803. The next prime is 19328901863. The reversal of 19328901821 is 12810982391.

It is a happy number.

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 14239648900 + 5089252921 = 119330^2 + 71339^2 .

It is a cyclic number.

It is not a de Polignac number, because 19328901821 - 2¹⁰ = 19328900797 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19328901881) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 132389666 + ... + 132389811.

It is an arithmetic number, because the mean of its divisors is an integer number (4898420343).

Almost surely, 2^19328901821 is an apocalyptic number.

It is an amenable number.

19328901821 is a deficient number, since it is larger than the sum of its proper divisors (264779551).

19328901821 is an equidigital number, since it uses as much as digits as its factorization.

19328901821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 264779550.

The product of its (nonzero) digits is 62208, while the sum is 44.

The spelling of 19328901821 in words is "nineteen billion, three hundred twenty-eight million, nine hundred one thousand, eight hundred twenty-one".