21222231021 has 6 divisors (see below), whose sum is σ = 30654333710. Its totient is φ = 14148154008.

The previous prime is 21222230947. The next prime is 21222231049. The reversal of 21222231021 is 12013222212.

It can be written as a sum of positive squares in only one way, i.e., 20833746921 + 388484100 = 144339^2 + 19710^2 .

It is not a de Polignac number, because 21222231021 - 2⁹ = 21222230509 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21222230985 and 21222231003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222231071) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1179012826 + ... + 1179012843.

Almost surely, 2^21222231021 is an apocalyptic number.

It is an amenable number.

21222231021 is a deficient number, since it is larger than the sum of its proper divisors (9432102689).

21222231021 is a wasteful number, since it uses less digits than its factorization.

21222231021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2358025675 (or 2358025672 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21222231021 its reverse (12013222212), we get a palindrome (33235453233).

The spelling of 21222231021 in words is "twenty-one billion, two hundred twenty-two million, two hundred thirty-one thousand, twenty-one".