21010220111 has 4 divisors (see below), whose sum is σ = 21013515000. Its totient is φ = 21006925224.

The previous prime is 21010220089. The next prime is 21010220129. The reversal of 21010220111 is 11102201012.

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

It is a cyclic number.

It is not a de Polignac number, because 21010220111 - 2⁶ = 21010220047 is a prime.

It is a super-2 number, since 2×21010220111² (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 = 21010220092 and 21010220101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010220171) 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, 1637861 + ... + 1650638.

It is an arithmetic number, because the mean of its divisors is an integer number (5253378750).

Almost surely, 2^21010220111 is an apocalyptic number.

21010220111 is a deficient number, since it is larger than the sum of its proper divisors (3294889).

21010220111 is an equidigital number, since it uses as much as digits as its factorization.

21010220111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3294888.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21010220111 its reverse (11102201012), we get a palindrome (32112421123).

The spelling of 21010220111 in words is "twenty-one billion, ten million, two hundred twenty thousand, one hundred eleven".