21643721148 has 48 divisors (see below), whose sum is σ = 59706823680. Its totient is φ = 5970681024.

The previous prime is 21643721147. The next prime is 21643721159. The reversal of 21643721148 is 84112734612.

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 polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4440036 + ... + 4444907.

It is an arithmetic number, because the mean of its divisors is an integer number (1243892160).

Almost surely, 2^21643721148 is an apocalyptic number.

21643721148 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21643721148 is an abundant number, since it is smaller than the sum of its proper divisors (38063102532).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21643721148 is a wasteful number, since it uses less digits than its factorization.

21643721148 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8884986 (or 8884984 counting only the distinct ones).

The product of its digits is 64512, while the sum is 39.

The spelling of 21643721148 in words is "twenty-one billion, six hundred forty-three million, seven hundred twenty-one thousand, one hundred forty-eight".