21021020223 has 32 divisors (see below), whose sum is σ = 33521319936. Its totient is φ = 11456547168.

The previous prime is 21021020161. The next prime is 21021020239. The reversal of 21021020223 is 32202012012.

It is a happy number.

It is not a de Polignac number, because 21021020223 - 2⁶ = 21021020159 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021020323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 104890 + ... + 230312.

It is an arithmetic number, because the mean of its divisors is an integer number (1047541248).

Almost surely, 2^21021020223 is an apocalyptic number.

21021020223 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21021020223 is a deficient number, since it is larger than the sum of its proper divisors (12500299713).

21021020223 is a wasteful number, since it uses less digits than its factorization.

21021020223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125803.

The product of its (nonzero) digits is 96, while the sum is 15.

Adding to 21021020223 its reverse (32202012012), we get a palindrome (53223032235).

The spelling of 21021020223 in words is "twenty-one billion, twenty-one million, twenty thousand, two hundred twenty-three".