21121230424 has 16 divisors (see below), whose sum is σ = 45259779600. Its totient is φ = 9051955872.

The previous prime is 21121230373. The next prime is 21121230451. The reversal of 21121230424 is 42403212112.

It is a super-2 number, since 2×21121230424² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21121230395 and 21121230404.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 188582359 + ... + 188582470.

It is an arithmetic number, because the mean of its divisors is an integer number (2828736225).

Almost surely, 2^21121230424 is an apocalyptic number.

It is an amenable number.

21121230424 is an abundant number, since it is smaller than the sum of its proper divisors (24138549176).

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

21121230424 is a wasteful number, since it uses less digits than its factorization.

21121230424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 377164842 (or 377164838 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 22.

Adding to 21121230424 its reverse (42403212112), we get a palindrome (63524442536).

The spelling of 21121230424 in words is "twenty-one billion, one hundred twenty-one million, two hundred thirty thousand, four hundred twenty-four".