21001021223 has 16 divisors (see below), whose sum is σ = 26006002176. Its totient is φ = 16514241120.

The previous prime is 21001021219. The next prime is 21001021229. The reversal of 21001021223 is 32212010012.

It is a happy number.

It is not a de Polignac number, because 21001021223 - 2² = 21001021219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21001021198 and 21001021207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001021229) 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 15 ways as a sum of consecutive naturals, for example, 693083 + ... + 722748.

It is an arithmetic number, because the mean of its divisors is an integer number (1625375136).

Almost surely, 2^21001021223 is an apocalyptic number.

21001021223 is a deficient number, since it is larger than the sum of its proper divisors (5004980953).

21001021223 is a wasteful number, since it uses less digits than its factorization.

21001021223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1416014.

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

Adding to 21001021223 its reverse (32212010012), we get a palindrome (53213031235).

The spelling of 21001021223 in words is "twenty-one billion, one million, twenty-one thousand, two hundred twenty-three".