21447723660 has 96 divisors (see below), whose sum is σ = 66623558400. Its totient is φ = 5111312640.

The previous prime is 21447723637. The next prime is 21447723683. The reversal of 21447723660 is 6632774412.

It is an interprime number because it is at equal distance from previous prime (21447723637) and next prime (21447723683).

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 236455 + ... + 314334.

It is an arithmetic number, because the mean of its divisors is an integer number (693995400).

Almost surely, 2^21447723660 is an apocalyptic number.

21447723660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21447723660 is an abundant number, since it is smaller than the sum of its proper divisors (45175834740).

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

21447723660 is a wasteful number, since it uses less digits than its factorization.

21447723660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 550871 (or 550869 counting only the distinct ones).

The product of its (nonzero) digits is 338688, while the sum is 42.

The spelling of 21447723660 in words is "twenty-one billion, four hundred forty-seven million, seven hundred twenty-three thousand, six hundred sixty".