21506202111124 has 24 divisors (see below), whose sum is σ = 37788380128800. Its totient is φ = 10709527932000.

The previous prime is 21506202111109. The next prime is 21506202111127. The reversal of 21506202111124 is 42111120260512.

It is a junction number, because it is equal to n+sod(n) for n = 21506202111092 and 21506202111101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21506202111127) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14113422 + ... + 15562810.

It is an arithmetic number, because the mean of its divisors is an integer number (1574515838700).

Almost surely, 2^{21506202111124} is an apocalyptic number.

It is an amenable number.

21506202111124 is a deficient number, since it is larger than the sum of its proper divisors (16282178017676).

21506202111124 is a wasteful number, since it uses less digits than its factorization.

21506202111124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1464423 (or 1464421 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 28.

Adding to 21506202111124 its reverse (42111120260512), we get a palindrome (63617322371636).

The spelling of 21506202111124 in words is "twenty-one trillion, five hundred six billion, two hundred two million, one hundred eleven thousand, one hundred twenty-four".