21728561360 has 80 divisors (see below), whose sum is σ = 55462914432. Its totient is φ = 7850918400.

The previous prime is 21728561353. The next prime is 21728561377. The reversal of 21728561360 is 6316582712.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 59525 + ... + 216795.

Almost surely, 2^21728561360 is an apocalyptic number.

21728561360 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21728561360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27731457216).

21728561360 is an abundant number, since it is smaller than the sum of its proper divisors (33734353072).

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

21728561360 is a wasteful number, since it uses less digits than its factorization.

21728561360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157452 (or 157446 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 41.

The spelling of 21728561360 in words is "twenty-one billion, seven hundred twenty-eight million, five hundred sixty-one thousand, three hundred sixty".