21604002289 has 3 divisors (see below), whose sum is σ = 21604149273. Its totient is φ = 21603855306.

The previous prime is 21604002247. The next prime is 21604002319. The reversal of 21604002289 is 98220040612.

The square root of 21604002289 is 146983.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 21604002289 - 2¹⁵ = 21603969521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21604002989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 73492 + ... + 220474.

It is an arithmetic number, because the mean of its divisors is an integer number (7201383091).

Almost surely, 2^21604002289 is an apocalyptic number.

21604002289 is the 146983-rd square number.

21604002289 is the 73492-nd centered octagonal number.

It is an amenable number.

21604002289 is a deficient number, since it is larger than the sum of its proper divisors (146984).

21604002289 is an frugal number, since it uses more digits than its factorization.

21604002289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 293966 (or 146983 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 34.

The spelling of 21604002289 in words is "twenty-one billion, six hundred four million, two thousand, two hundred eighty-nine".