21110012001 has 12 divisors (see below), whose sum is σ = 32837796628. Its totient is φ = 12990776544.

The previous prime is 21110011991. The next prime is 21110012003. The reversal of 21110012001 is 10021001112.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 1789290000 + 19320722001 = 42300^2 + 138999^2 .

It is not a de Polignac number, because 21110012001 - 2⁵ = 21110011969 is a prime.

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

It is not an unprimeable number, because it can be changed into a prime (21110012003) 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, 90213610 + ... + 90213843.

Almost surely, 2^21110012001 is an apocalyptic number.

It is an amenable number.

21110012001 is a deficient number, since it is larger than the sum of its proper divisors (11727784627).

21110012001 is a wasteful number, since it uses less digits than its factorization.

21110012001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180427472 (or 180427469 counting only the distinct ones).

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

Adding to 21110012001 its reverse (10021001112), we get a palindrome (31131013113).

The spelling of 21110012001 in words is "twenty-one billion, one hundred ten million, twelve thousand, one".