21161017111 has 12 divisors (see below), whose sum is σ = 23446892568. Its totient is φ = 19078978464.

The previous prime is 21161017103. The next prime is 21161017127. The reversal of 21161017111 is 11171016112.

It is not a de Polignac number, because 21161017111 - 2³ = 21161017103 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 (21161017151) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1448700 + ... + 1463233.

It is an arithmetic number, because the mean of its divisors is an integer number (1953907714).

Almost surely, 2^21161017111 is an apocalyptic number.

21161017111 is a deficient number, since it is larger than the sum of its proper divisors (2285875457).

21161017111 is a wasteful number, since it uses less digits than its factorization.

21161017111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2912002 (or 2911989 counting only the distinct ones).

The product of its (nonzero) digits is 84, while the sum is 22.

Subtracting from 21161017111 its reverse (11171016112), we obtain a palindrome (9990000999).

It can be divided in two parts, 2116101 and 7111, that added together give a palindrome (2123212).

The spelling of 21161017111 in words is "twenty-one billion, one hundred sixty-one million, seventeen thousand, one hundred eleven".