21220220421023 has 4 divisors (see below), whose sum is σ = 22852545068808. Its totient is φ = 19587895773240.

The previous prime is 21220220420999. The next prime is 21220220421061. The reversal of 21220220421023 is 32012402202212.

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 21220220421023 - 2²⁶ = 21220153312159 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21220220421023.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220220421523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 816162323873 + ... + 816162323898.

It is an arithmetic number, because the mean of its divisors is an integer number (5713136267202).

Almost surely, 2^{21220220421023} is an apocalyptic number.

21220220421023 is a deficient number, since it is larger than the sum of its proper divisors (1632324647785).

21220220421023 is a wasteful number, since it uses less digits than its factorization.

21220220421023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1632324647784.

The product of its (nonzero) digits is 1536, while the sum is 23.

Adding to 21220220421023 its reverse (32012402202212), we get a palindrome (53232622623235).

The spelling of 21220220421023 in words is "twenty-one trillion, two hundred twenty billion, two hundred twenty million, four hundred twenty-one thousand, twenty-three".