18929921827609 has 9 divisors (see below), whose sum is σ = 20498142279069. Its totient is φ = 17473721784480.

The previous prime is 18929921827591. The next prime is 18929921827703. The reversal of 18929921827609 is 90672812992981.

The square root of 18929921827609 is 4350853.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 7104383814025 + 11825538013584 = 2665405^2 + 3438828^2 .

It is not a de Polignac number, because 18929921827609 - 2⁵ = 18929921827577 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18929921824609) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 56393749 + ... + 56728429.

It is an arithmetic number, because the mean of its divisors is an integer number (2277571364341).

Almost surely, 2^{18929921827609} is an apocalyptic number.

18929921827609 is the 4350853-rd square number.

18929921827609 is the 2175427-th centered octagonal number.

It is an amenable number.

18929921827609 is a deficient number, since it is larger than the sum of its proper divisors (1568220451460).

18929921827609 is an frugal number, since it uses more digits than its factorization.

18929921827609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 669388 (or 334694 counting only the distinct ones).

The product of its (nonzero) digits is 141087744, while the sum is 73.

The spelling of 18929921827609 in words is "eighteen trillion, nine hundred twenty-nine billion, nine hundred twenty-one million, eight hundred twenty-seven thousand, six hundred nine".