21021020222220 has 144 divisors (see below), whose sum is σ = 67134972253440. Its totient is φ = 5309369036928.

The previous prime is 21021020222161. The next prime is 21021020222249. The reversal of 21021020222220 is 2222202012012.

21021020222220 is a `hidden beast` number, since 2 + 10 + 210 + 2 + 0 + 222 + 220 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21021020222193 and 21021020222202.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 14431827 + ... + 15821493.

Almost surely, 2^{21021020222220} is an apocalyptic number.

21021020222220 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 21021020222220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33567486126720).

21021020222220 is an abundant number, since it is smaller than the sum of its proper divisors (46113952031220).

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

21021020222220 is a wasteful number, since it uses less digits than its factorization.

21021020222220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1394124 (or 1394119 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

Adding to 21021020222220 its reverse (2222202012012), we get a palindrome (23243222234232).

The spelling of 21021020222220 in words is "twenty-one trillion, twenty-one billion, twenty million, two hundred twenty-two thousand, two hundred twenty".