21111212122 has 64 divisors (see below), whose sum is σ = 43422511104. Its totient is φ = 7430869440.

The previous prime is 21111212077. The next prime is 21111212123. The reversal of 21111212122 is 22121211112.

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 = 21111212096 and 21111212105.

It is not an unprimeable number, because it can be changed into a prime (21111212123) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18088 + ... + 206275.

It is an arithmetic number, because the mean of its divisors is an integer number (678476736).

Almost surely, 2^21111212122 is an apocalyptic number.

21111212122 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21111212122 is an abundant number, since it is smaller than the sum of its proper divisors (22311298982).

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

21111212122 is a wasteful number, since it uses less digits than its factorization.

21111212122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 224443.

The product of its digits is 32, while the sum is 16.

Adding to 21111212122 its reverse (22121211112), we get a palindrome (43232423234).

The spelling of 21111212122 in words is "twenty-one billion, one hundred eleven million, two hundred twelve thousand, one hundred twenty-two".