21643721149 has 8 divisors (see below), whose sum is σ = 21675745280. Its totient is φ = 21611721456.

The previous prime is 21643721147. The next prime is 21643721159. The reversal of 21643721149 is 94112734612.

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

It is a cyclic number.

It is not a de Polignac number, because 21643721149 - 2¹ = 21643721147 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 (21643721147) 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, 2429347 + ... + 2438239.

It is an arithmetic number, because the mean of its divisors is an integer number (2709468160).

Almost surely, 2^21643721149 is an apocalyptic number.

It is an amenable number.

21643721149 is a deficient number, since it is larger than the sum of its proper divisors (32024131).

21643721149 is a wasteful number, since it uses less digits than its factorization.

21643721149 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12219.

The product of its digits is 72576, while the sum is 40.

The spelling of 21643721149 in words is "twenty-one billion, six hundred forty-three million, seven hundred twenty-one thousand, one hundred forty-nine".