21011023220 has 36 divisors (see below), whose sum is σ = 48499003812. Its totient is φ = 7640371200.

The previous prime is 21011023211. The next prime is 21011023223. The reversal of 21011023220 is 2232011012.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 16248091024 + 4762932196 = 127468^2 + 69014^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21011023195 and 21011023204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011023223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4338701 + ... + 4343540.

Almost surely, 2^21011023220 is an apocalyptic number.

21011023220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21011023220 is an abundant number, since it is smaller than the sum of its proper divisors (27487980592).

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

21011023220 is a wasteful number, since it uses less digits than its factorization.

21011023220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8682272 (or 8682259 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 21011023220 its reverse (2232011012), we get a palindrome (23243034232).

The spelling of 21011023220 in words is "twenty-one billion, eleven million, twenty-three thousand, two hundred twenty".