21604643349 has 8 divisors (see below), whose sum is σ = 29735423232. Its totient is φ = 13938479520.

The previous prime is 21604643311. The next prime is 21604643351. The reversal of 21604643349 is 94334640612.

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

It is not a de Polignac number, because 21604643349 - 2¹⁵ = 21604610581 is a prime.

It is a super-2 number, since 2×21604643349² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21604643349.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21604643309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 116153904 + ... + 116154089.

It is an arithmetic number, because the mean of its divisors is an integer number (3716927904).

Almost surely, 2^21604643349 is an apocalyptic number.

It is an amenable number.

21604643349 is a deficient number, since it is larger than the sum of its proper divisors (8130779883).

21604643349 is a wasteful number, since it uses less digits than its factorization.

21604643349 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232308027.

The product of its (nonzero) digits is 373248, while the sum is 42.

The spelling of 21604643349 in words is "twenty-one billion, six hundred four million, six hundred forty-three thousand, three hundred forty-nine".