21245405124 has 24 divisors (see below), whose sum is σ = 49578910528. Its totient is φ = 7080901920.

The previous prime is 21245405089. The next prime is 21245405147. The reversal of 21245405124 is 42150454212.

It is a junction number, because it is equal to n+sod(n) for n = 21245405091 and 21245405100.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10387 + ... + 206394.

Almost surely, 2^21245405124 is an apocalyptic number.

It is an amenable number.

21245405124 is an abundant number, since it is smaller than the sum of its proper divisors (28333505404).

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

21245405124 is a wasteful number, since it uses less digits than its factorization.

21245405124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 224955 (or 224953 counting only the distinct ones).

The product of its (nonzero) digits is 12800, while the sum is 30.

Adding to 21245405124 its reverse (42150454212), we get a palindrome (63395859336).

The spelling of 21245405124 in words is "twenty-one billion, two hundred forty-five million, four hundred five thousand, one hundred twenty-four".