21121200111 has 8 divisors (see below), whose sum is σ = 30721745664. Its totient is φ = 12800727320.

The previous prime is 21121200101. The next prime is 21121200119. The reversal of 21121200111 is 11100212112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21121200111 - 2⁹ = 21121199599 is a prime.

It is a super-2 number, since 2×21121200111² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121200119) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 320018151 + ... + 320018216.

It is an arithmetic number, because the mean of its divisors is an integer number (3840218208).

Almost surely, 2^21121200111 is an apocalyptic number.

21121200111 is a deficient number, since it is larger than the sum of its proper divisors (9600545553).

21121200111 is a wasteful number, since it uses less digits than its factorization.

21121200111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 640036381.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21121200111 its reverse (11100212112), we get a palindrome (32221412223).

The spelling of 21121200111 in words is "twenty-one billion, one hundred twenty-one million, two hundred thousand, one hundred eleven".