21012001122 has 128 divisors (see below), whose sum is σ = 51411677184. Its totient is φ = 5588563968.

The previous prime is 21012001121. The next prime is 21012001163. The reversal of 21012001122 is 22110021012.

It is a junction number, because it is equal to n+sod(n) for n = 21012001098 and 21012001107.

It is not an unprimeable number, because it can be changed into a prime (21012001121) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 37321213 + ... + 37321775.

It is an arithmetic number, because the mean of its divisors is an integer number (401653728).

Almost surely, 2^21012001122 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21012001122, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25705838592).

21012001122 is an abundant number, since it is smaller than the sum of its proper divisors (30399676062).

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

21012001122 is a wasteful number, since it uses less digits than its factorization.

21012001122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1072.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21012001122 its reverse (22110021012), we get a palindrome (43122022134).

The spelling of 21012001122 in words is "twenty-one billion, twelve million, one thousand, one hundred twenty-two".