21121100121111 has 8 divisors (see below), whose sum is σ = 29818023700464. Its totient is φ = 13252454977920.

The previous prime is 21121100121103. The next prime is 21121100121113. The reversal of 21121100121111 is 11112100112112.

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

It is not a de Polignac number, because 21121100121111 - 2³ = 21121100121103 is a prime.

It is a super-2 number, since 2×21121100121111² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121100121113) 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, 207069608980 + ... + 207069609081.

It is an arithmetic number, because the mean of its divisors is an integer number (3727252962558).

Almost surely, 2^{21121100121111} is an apocalyptic number.

21121100121111 is a deficient number, since it is larger than the sum of its proper divisors (8696923579353).

21121100121111 is a wasteful number, since it uses less digits than its factorization.

21121100121111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 414139218081.

The product of its (nonzero) digits is 8, while the sum is 15.

Adding to 21121100121111 its reverse (11112100112112), we get a palindrome (32233200233223).

It can be divided in two parts, 211211001 and 21111, that added together give a palindrome (211232112).

The spelling of 21121100121111 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred million, one hundred twenty-one thousand, one hundred eleven".