19722128749 has 4 divisors (see below), whose sum is σ = 19903065820. Its totient is φ = 19541191680.

The previous prime is 19722128743. The next prime is 19722128753. The reversal of 19722128749 is 94782122791.

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 12140073124 + 7582055625 = 110182^2 + 87075^2 .

It is a cyclic number.

It is not a de Polignac number, because 19722128749 - 2⁵ = 19722128717 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19722128696 and 19722128705.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19722128743) 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, 90468372 + ... + 90468589.

It is an arithmetic number, because the mean of its divisors is an integer number (4975766455).

Almost surely, 2^19722128749 is an apocalyptic number.

It is an amenable number.

19722128749 is a deficient number, since it is larger than the sum of its proper divisors (180937071).

19722128749 is a wasteful number, since it uses less digits than its factorization.

19722128749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180937070.

The product of its digits is 1016064, while the sum is 52.

The spelling of 19722128749 in words is "nineteen billion, seven hundred twenty-two million, one hundred twenty-eight thousand, seven hundred forty-nine".