21531223122 has 16 divisors (see below), whose sum is σ = 43095817632. Its totient is φ = 7171512480.

The previous prime is 21531223121. The next prime is 21531223123. The reversal of 21531223122 is 22132213512.

It is an interprime number because it is at equal distance from previous prime (21531223121) and next prime (21531223123).

It is a junction number, because it is equal to n+sod(n) for n = 21531223092 and 21531223101.

It is not an unprimeable number, because it can be changed into a prime (21531223121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1382083 + ... + 1397574.

It is an arithmetic number, because the mean of its divisors is an integer number (2693488602).

Almost surely, 2^21531223122 is an apocalyptic number.

21531223122 is an abundant number, since it is smaller than the sum of its proper divisors (21564594510).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21531223122 is a wasteful number, since it uses less digits than its factorization.

21531223122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2780953.

The product of its digits is 1440, while the sum is 24.

Adding to 21531223122 its reverse (22132213512), we get a palindrome (43663436634).

The spelling of 21531223122 in words is "twenty-one billion, five hundred thirty-one million, two hundred twenty-three thousand, one hundred twenty-two".