21222750720 has 160 divisors (see below), whose sum is σ = 71417839680. Its totient is φ = 5361500160.

The previous prime is 21222750707. The next prime is 21222750721. The reversal of 21222750720 is 2705722212.

It is a tau number, because it is divible by the number of its divisors (160).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (21222750721) 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, 73200 + ... + 218640.

It is an arithmetic number, because the mean of its divisors is an integer number (446361498).

Almost surely, 2^21222750720 is an apocalyptic number.

21222750720 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 21222750720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35708919840).

21222750720 is an abundant number, since it is smaller than the sum of its proper divisors (50195088960).

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

21222750720 is a wasteful number, since it uses less digits than its factorization.

21222750720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145486 (or 145470 counting only the distinct ones).

The product of its (nonzero) digits is 7840, while the sum is 30.

The spelling of 21222750720 in words is "twenty-one billion, two hundred twenty-two million, seven hundred fifty thousand, seven hundred twenty".