211111310021 has 4 divisors (see below), whose sum is σ = 211896110700. Its totient is φ = 210326509344.

The previous prime is 211111309987. The next prime is 211111310041. The reversal of 211111310021 is 120013111112.

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 34510492900 + 176600817121 = 185770^2 + 420239^2 .

It is a cyclic number.

It is not a de Polignac number, because 211111310021 - 2²² = 211107115717 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 211111309978 and 211111310005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211111310041) 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, 392399936 + ... + 392400473.

It is an arithmetic number, because the mean of its divisors is an integer number (52974027675).

Almost surely, 2^211111310021 is an apocalyptic number.

It is an amenable number.

211111310021 is a deficient number, since it is larger than the sum of its proper divisors (784800679).

211111310021 is an equidigital number, since it uses as much as digits as its factorization.

211111310021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 784800678.

The product of its (nonzero) digits is 12, while the sum is 14.

Adding to 211111310021 its reverse (120013111112), we get a palindrome (331124421133).

The spelling of 211111310021 in words is "two hundred eleven billion, one hundred eleven million, three hundred ten thousand, twenty-one".