21110001012 has 18 divisors (see below), whose sum is σ = 53361391538. Its totient is φ = 7036666992.

The previous prime is 21110001007. The next prime is 21110001019. The reversal of 21110001012 is 21010001112.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 15039097956 + 6070903056 = 122634^2 + 77916^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21110000985 and 21110001003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110001019) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 293194423 + ... + 293194494.

Almost surely, 2^21110001012 is an apocalyptic number.

It is an amenable number.

21110001012 is an abundant number, since it is smaller than the sum of its proper divisors (32251390526).

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

21110001012 is a wasteful number, since it uses less digits than its factorization.

21110001012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 586388927 (or 586388922 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21110001012 its reverse (21010001112), we get a palindrome (42120002124).

The spelling of 21110001012 in words is "twenty-one billion, one hundred ten million, one thousand, twelve".