211121100110021 has 4 divisors (see below), whose sum is σ = 211121129173452. Its totient is φ = 211121071046592.

The previous prime is 211121100110017. The next prime is 211121100110023. The reversal of 211121100110021 is 120011001121112.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 138527956644100 + 72593143465921 = 11769790^2 + 8520161^2 .

It is a cyclic number.

It is not a de Polignac number, because 211121100110021 - 2² = 211121100110017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 211121100109978 and 211121100110005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211121100110023) 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, 6931655 + ... + 21686171.

It is an arithmetic number, because the mean of its divisors is an integer number (52780282293363).

Almost surely, 2^{211121100110021} is an apocalyptic number.

It is an amenable number.

211121100110021 is a deficient number, since it is larger than the sum of its proper divisors (29063431).

211121100110021 is a wasteful number, since it uses less digits than its factorization.

211121100110021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29063430.

The product of its (nonzero) digits is 8, while the sum is 14.

Adding to 211121100110021 its reverse (120011001121112), we get a palindrome (331132101231133).

The spelling of 211121100110021 in words is "two hundred eleven trillion, one hundred twenty-one billion, one hundred million, one hundred ten thousand, twenty-one".