21211012111 has 4 divisors (see below), whose sum is σ = 21271789000. Its totient is φ = 21150235224.

The previous prime is 21211012099. The next prime is 21211012117. The reversal of 21211012111 is 11121011212.

It is a happy number.

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 21211012111 - 2⁹ = 21211011599 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21211012091 and 21211012100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211012117) 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, 30387921 + ... + 30388618.

It is an arithmetic number, because the mean of its divisors is an integer number (5317947250).

Almost surely, 2^21211012111 is an apocalyptic number.

21211012111 is a deficient number, since it is larger than the sum of its proper divisors (60776889).

21211012111 is an equidigital number, since it uses as much as digits as its factorization.

21211012111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60776888.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21211012111 its reverse (11121011212), we get a palindrome (32332023323).

It can be divided in two parts, 2121101 and 2111, that added together give a palindrome (2123212).

The spelling of 21211012111 in words is "twenty-one billion, two hundred eleven million, twelve thousand, one hundred eleven".