21121101101 has 4 divisors (see below), whose sum is σ = 21230537052. Its totient is φ = 21011665152.

The previous prime is 21121101097. The next prime is 21121101103. The reversal of 21121101101 is 10110112112.

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 12748668100 + 8372433001 = 112910^2 + 91501^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121101101 - 2² = 21121101097 is a prime.

It is a super-2 number, since 2×21121101101² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121101103) 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, 54717686 + ... + 54718071.

It is an arithmetic number, because the mean of its divisors is an integer number (5307634263).

Almost surely, 2^21121101101 is an apocalyptic number.

It is an amenable number.

21121101101 is a deficient number, since it is larger than the sum of its proper divisors (109435951).

21121101101 is a wasteful number, since it uses less digits than its factorization.

21121101101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109435950.

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 21121101101 its reverse (10110112112), we get a palindrome (31231213213).

The spelling of 21121101101 in words is "twenty-one billion, one hundred twenty-one million, one hundred one thousand, one hundred one".