21020031223 has 4 divisors (see below), whose sum is σ = 21933945648. Its totient is φ = 20106116800.

The previous prime is 21020031161. The next prime is 21020031251. The reversal of 21020031223 is 32213002012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21020031223 - 2³³ = 12430096631 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21020031197 and 21020031206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020031023) 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 3 ways as a sum of consecutive naturals, for example, 456957178 + ... + 456957223.

It is an arithmetic number, because the mean of its divisors is an integer number (5483486412).

Almost surely, 2^21020031223 is an apocalyptic number.

21020031223 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21020031223 is a deficient number, since it is larger than the sum of its proper divisors (913914425).

21020031223 is an equidigital number, since it uses as much as digits as its factorization.

21020031223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 913914424.

The product of its (nonzero) digits is 144, while the sum is 16.

Adding to 21020031223 its reverse (32213002012), we get a palindrome (53233033235).

The spelling of 21020031223 in words is "twenty-one billion, twenty million, thirty-one thousand, two hundred twenty-three".