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21000221220 = 2235111092511163
BaseRepresentation
bin10011100011101101…
…011111001000100100
32000012112121202211010
4103203231133020210
5321002024034340
613351455342220
71342255635516
oct234355371044
960175552733
1021000221220
1189a7094030
1240a0b21970
131c98991704
14103308dbb6
1582d992b80
hex4e3b5f224

21000221220 has 192 divisors, whose sum is σ = 65048417280. Its totient is φ = 5019840000.

The previous prime is 21000221189. The next prime is 21000221243. The reversal of 21000221220 is 2212200012.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21000221196 and 21000221205.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 18056359 + ... + 18057521.

It is an arithmetic number, because the mean of its divisors is an integer number (338793840).

Almost surely, 221000221220 is an apocalyptic number.

21000221220 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 21000221220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32524208640).

21000221220 is an abundant number, since it is smaller than the sum of its proper divisors (44048196060).

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

21000221220 is a wasteful number, since it uses less digits than its factorization.

21000221220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1546 (or 1544 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

Adding to 21000221220 its reverse (2212200012), we get a palindrome (23212421232).

The spelling of 21000221220 in words is "twenty-one billion, two hundred twenty-one thousand, two hundred twenty".