21111021124 has 18 divisors (see below), whose sum is σ = 39245317370. Its totient is φ = 9934597632.

The previous prime is 21111021101. The next prime is 21111021131. The reversal of 21111021124 is 42112011112.

It can be written as a sum of positive squares in 3 ways, for example, as 16187472900 + 4923548224 = 127230^2 + 70168^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21111021098 and 21111021107.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9129909 + ... + 9132220.

Almost surely, 2^21111021124 is an apocalyptic number.

It is an amenable number.

21111021124 is a deficient number, since it is larger than the sum of its proper divisors (18134296246).

21111021124 is a wasteful number, since it uses less digits than its factorization.

21111021124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18262167 (or 18262148 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21111021124 its reverse (42112011112), we get a palindrome (63223032236).

The spelling of 21111021124 in words is "twenty-one billion, one hundred eleven million, twenty-one thousand, one hundred twenty-four".