21643738860 has 24 divisors (see below), whose sum is σ = 60602468976. Its totient is φ = 5771663680.

The previous prime is 21643738859. The next prime is 21643738873. The reversal of 21643738860 is 6883734612.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 180364431 + ... + 180364550.

It is an arithmetic number, because the mean of its divisors is an integer number (2525102874).

Almost surely, 2^21643738860 is an apocalyptic number.

21643738860 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21643738860 is an abundant number, since it is smaller than the sum of its proper divisors (38958730116).

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

21643738860 is a wasteful number, since it uses less digits than its factorization.

21643738860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360728993 (or 360728991 counting only the distinct ones).

The product of its (nonzero) digits is 1161216, while the sum is 48.

The spelling of 21643738860 in words is "twenty-one billion, six hundred forty-three million, seven hundred thirty-eight thousand, eight hundred sixty".