21221222211021 has 48 divisors (see below), whose sum is σ = 34221627654144. Its totient is φ = 11456875999008.

The previous prime is 21221222211017. The next prime is 21221222211029. The reversal of 21221222211021 is 12011222212212.

It is not a de Polignac number, because 21221222211021 - 2² = 21221222211017 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221222211029) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1031485 + ... + 6595938.

It is an arithmetic number, because the mean of its divisors is an integer number (712950576128).

Almost surely, 2^{21221222211021} is an apocalyptic number.

21221222211021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21221222211021 is a deficient number, since it is larger than the sum of its proper divisors (13000405443123).

21221222211021 is a wasteful number, since it uses less digits than its factorization.

21221222211021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7627838 (or 7627819 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 21.

Adding to 21221222211021 its reverse (12011222212212), we get a palindrome (33232444423233).

The spelling of 21221222211021 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred twenty-two million, two hundred eleven thousand, twenty-one".