21111101022172 has 12 divisors (see below), whose sum is σ = 42222202044400. Its totient is φ = 9047614723776.

The previous prime is 21111101022107. The next prime is 21111101022173. The reversal of 21111101022172 is 27122010111112.

21111101022172 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111101022173) 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, 376983946797 + ... + 376983946852.

Almost surely, 2^{21111101022172} is an apocalyptic number.

It is an amenable number.

21111101022172 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21111101022172 is a wasteful number, since it uses less digits than its factorization.

21111101022172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 753967893660 (or 753967893658 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 22.

Adding to 21111101022172 its reverse (27122010111112), we get a palindrome (48233111133284).

The spelling of 21111101022172 in words is "twenty-one trillion, one hundred eleven billion, one hundred one million, twenty-two thousand, one hundred seventy-two".