21121031101 has 4 divisors (see below), whose sum is σ = 21121339932. Its totient is φ = 21120722272.

The previous prime is 21121031083. The next prime is 21121031117. The reversal of 21121031101 is 10113012112.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 8118190201 + 13002840900 = 90101^2 + 114030^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121031101 - 2⁵ = 21121031069 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121031501) 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, 1066 + ... + 205531.

It is an arithmetic number, because the mean of its divisors is an integer number (5280334983).

Almost surely, 2^21121031101 is an apocalyptic number.

It is an amenable number.

21121031101 is a deficient number, since it is larger than the sum of its proper divisors (308831).

21121031101 is a wasteful number, since it uses less digits than its factorization.

21121031101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308830.

The product of its (nonzero) digits is 12, while the sum is 13.

Adding to 21121031101 its reverse (10113012112), we get a palindrome (31234043213).

The spelling of 21121031101 in words is "twenty-one billion, one hundred twenty-one million, thirty-one thousand, one hundred one".