21111000121 has 8 divisors (see below), whose sum is σ = 21511724040. Its totient is φ = 20710365312.

The previous prime is 21111000091. The next prime is 21111000137. The reversal of 21111000121 is 12100011112.

It can be written as a sum of positive squares in 4 ways, for example, as 82810000 + 21028190121 = 9100^2 + 145011^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21111000121 - 2¹³ = 21110991929 is a prime.

It is a super-2 number, since 2×21111000121² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21111000098 and 21111000107.

It is not an unprimeable number, because it can be changed into a prime (21111000181) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 641845 + ... + 673933.

It is an arithmetic number, because the mean of its divisors is an integer number (2688965505).

Almost surely, 2^21111000121 is an apocalyptic number.

It is an amenable number.

21111000121 is a deficient number, since it is larger than the sum of its proper divisors (400723919).

21111000121 is a wasteful number, since it uses less digits than its factorization.

21111000121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44555.

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 21111000121 its reverse (12100011112), we get a palindrome (33211011233).

The spelling of 21111000121 in words is "twenty-one billion, one hundred eleven million, one hundred twenty-one", and thus it is an aban number.