21122011220 has 12 divisors (see below), whose sum is σ = 44356223604. Its totient is φ = 8448804480.

The previous prime is 21122011217. The next prime is 21122011243. The reversal of 21122011220 is 2211022112.

It can be written as a sum of positive squares in 2 ways, for example, as 8478358084 + 12643653136 = 92078^2 + 112444^2 .

It is a super-2 number, since 2×21122011220² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21122011195 and 21122011204.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 528050261 + ... + 528050300.

It is an arithmetic number, because the mean of its divisors is an integer number (3696351967).

Almost surely, 2^21122011220 is an apocalyptic number.

21122011220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21122011220 is an abundant number, since it is smaller than the sum of its proper divisors (23234212384).

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

21122011220 is a wasteful number, since it uses less digits than its factorization.

21122011220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1056100570 (or 1056100568 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21122011220 its reverse (2211022112), we get a palindrome (23333033332).

The spelling of 21122011220 in words is "twenty-one billion, one hundred twenty-two million, eleven thousand, two hundred twenty".