21311031101 has 4 divisors (see below), whose sum is σ = 21321244512. Its totient is φ = 21300817692.

The previous prime is 21311031083. The next prime is 21311031107. The reversal of 21311031101 is 10113011312.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21311031101 - 2¹⁸ = 21310768957 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 (21311031107) 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, 5103575 + ... + 5107748.

It is an arithmetic number, because the mean of its divisors is an integer number (5330311128).

Almost surely, 2^21311031101 is an apocalyptic number.

It is an amenable number.

21311031101 is a deficient number, since it is larger than the sum of its proper divisors (10213411).

21311031101 is a wasteful number, since it uses less digits than its factorization.

21311031101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10213410.

The product of its (nonzero) digits is 18, while the sum is 14.

Adding to 21311031101 its reverse (10113011312), we get a palindrome (31424042413).

The spelling of 21311031101 in words is "twenty-one billion, three hundred eleven million, thirty-one thousand, one hundred one".