21311212122 has 24 divisors (see below), whose sum is σ = 47422248276. Its totient is φ = 6911744256.

The previous prime is 21311212099. The next prime is 21311212127. The reversal of 21311212122 is 22121211312.

21311212122 is a `hidden beast` number, since 21 + 311 + 212 + 122 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 15145978761 + 6165233361 = 123069^2 + 78519^2 .

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 = 21311212095 and 21311212104.

It is not an unprimeable number, because it can be changed into a prime (21311212127) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15998743 + ... + 16000074.

Almost surely, 2^21311212122 is an apocalyptic number.

21311212122 is an abundant number, since it is smaller than the sum of its proper divisors (26111036154).

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

21311212122 is a wasteful number, since it uses less digits than its factorization.

21311212122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31998862 (or 31998859 counting only the distinct ones).

The product of its digits is 96, while the sum is 18.

Adding to 21311212122 its reverse (22121211312), we get a palindrome (43432423434).

The spelling of 21311212122 in words is "twenty-one billion, three hundred eleven million, two hundred twelve thousand, one hundred twenty-two".