121111100000021 has 4 divisors (see below), whose sum is σ = 121422439589100. Its totient is φ = 120799760410944.

The previous prime is 121111099999973. The next prime is 121111100000047. The reversal of 121111100000021 is 120000001111121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19261223115121 + 101849876884900 = 4388761^2 + 10092070^2 .

It is a cyclic number.

It is not a de Polignac number, because 121111100000021 - 2⁶ = 121111099999957 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 121111099999948 and 121111100000011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121111100000221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 155669793956 + ... + 155669794733.

It is an arithmetic number, because the mean of its divisors is an integer number (30355609897275).

Almost surely, 2^{121111100000021} is an apocalyptic number.

It is an amenable number.

121111100000021 is a deficient number, since it is larger than the sum of its proper divisors (311339589079).

121111100000021 is an equidigital number, since it uses as much as digits as its factorization.

121111100000021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311339589078.

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 121111100000021 its reverse (120000001111121), we get a palindrome (241111101111142).

The spelling of 121111100000021 in words is "one hundred twenty-one trillion, one hundred eleven billion, one hundred million, twenty-one", and thus it is an aban number.