21730870356820 has 96 divisors (see below), whose sum is σ = 48314605248000. Its totient is φ = 8187232204800.

The previous prime is 21730870356787. The next prime is 21730870356821. The reversal of 21730870356820 is 2865307803712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21730870356821) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 278451205 + ... + 278529235.

It is an arithmetic number, because the mean of its divisors is an integer number (503277138000).

Almost surely, 2^{21730870356820} is an apocalyptic number.

21730870356820 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 21730870356820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24157302624000).

21730870356820 is an abundant number, since it is smaller than the sum of its proper divisors (26583734891180).

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

21730870356820 is a wasteful number, since it uses less digits than its factorization.

21730870356820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82289 (or 82287 counting only the distinct ones).

The product of its (nonzero) digits is 3386880, while the sum is 52.

The spelling of 21730870356820 in words is "twenty-one trillion, seven hundred thirty billion, eight hundred seventy million, three hundred fifty-six thousand, eight hundred twenty".