2111211220021 has 4 divisors (see below), whose sum is σ = 2116529132812. Its totient is φ = 2105893307232.

The previous prime is 2111211219989. The next prime is 2111211220081. The reversal of 2111211220021 is 1200221121112.

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 1224950900625 + 886260319396 = 1106775^2 + 941414^2 .

It is a cyclic number.

It is not a de Polignac number, because 2111211220021 - 2⁵ = 2111211219989 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2111211219977 and 2111211220004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2111211220081) 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, 2658955800 + ... + 2658956593.

It is an arithmetic number, because the mean of its divisors is an integer number (529132283203).

Almost surely, 2^{2111211220021} is an apocalyptic number.

It is an amenable number.

2111211220021 is a deficient number, since it is larger than the sum of its proper divisors (5317912791).

2111211220021 is an equidigital number, since it uses as much as digits as its factorization.

2111211220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5317912790.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 2111211220021 its reverse (1200221121112), we get a palindrome (3311432341133).

The spelling of 2111211220021 in words is "two trillion, one hundred eleven billion, two hundred eleven million, two hundred twenty thousand, twenty-one".