21221212122 has 24 divisors (see below), whose sum is σ = 50159229120. Its totient is φ = 6430670280.

The previous prime is 21221212109. The next prime is 21221212139. The reversal of 21221212122 is 22121212212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 21221212095 and 21221212104.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 53588722 + ... + 53589117.

It is an arithmetic number, because the mean of its divisors is an integer number (2089967880).

Almost surely, 2^21221212122 is an apocalyptic number.

21221212122 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21221212122 is an abundant number, since it is smaller than the sum of its proper divisors (28938016998).

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

21221212122 is a wasteful number, since it uses less digits than its factorization.

21221212122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107177858 (or 107177855 counting only the distinct ones).

The product of its digits is 128, while the sum is 18.

Adding to 21221212122 its reverse (22121212212), we get a palindrome (43342424334).

The spelling of 21221212122 in words is "twenty-one billion, two hundred twenty-one million, two hundred twelve thousand, one hundred twenty-two".