21101204124 has 432 divisors, whose sum is σ = 74383755264. Its totient is φ = 4892659200.

The previous prime is 21101204107. The next prime is 21101204171. The reversal of 21101204124 is 42140210112.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21101204097 and 21101204106.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 14521782 + ... + 14523234.

Almost surely, 2^21101204124 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21101204124, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37191877632).

21101204124 is an abundant number, since it is smaller than the sum of its proper divisors (53282551140).

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

21101204124 is a wasteful number, since it uses less digits than its factorization.

21101204124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1538 (or 1520 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21101204124 its reverse (42140210112), we get a palindrome (63241414236).

The spelling of 21101204124 in words is "twenty-one billion, one hundred one million, two hundred four thousand, one hundred twenty-four".