21110000121 has 36 divisors (see below), whose sum is σ = 37557060372. Its totient is φ = 11353273344.

The previous prime is 21110000101. The next prime is 21110000137. The reversal of 21110000121 is 12100001112.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 9368110521 + 11741889600 = 96789^2 + 108360^2 .

It is not a de Polignac number, because 21110000121 - 2⁶ = 21110000057 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 (21110000101) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1400400 + ... + 1415393.

It is an arithmetic number, because the mean of its divisors is an integer number (1043251677).

Almost surely, 2^21110000121 is an apocalyptic number.

21110000121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21110000121 is a deficient number, since it is larger than the sum of its proper divisors (16447060251).

21110000121 is a wasteful number, since it uses less digits than its factorization.

21110000121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2815830 (or 2815820 counting only the distinct ones).

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

Adding to 21110000121 its reverse (12100001112), we get a palindrome (33210001233).

Subtracting from 21110000121 its reverse (12100001112), we obtain a palindrome (9009999009).

The spelling of 21110000121 in words is "twenty-one billion, one hundred ten million, one hundred twenty-one", and thus it is an aban number.