21125033421 has 32 divisors (see below), whose sum is σ = 29941874688. Its totient is φ = 13226915520.

The previous prime is 21125033417. The next prime is 21125033429. The reversal of 21125033421 is 12433052112.

It is not a de Polignac number, because 21125033421 - 2² = 21125033417 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21125033391 and 21125033400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21125033429) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 611020 + ... + 644666.

It is an arithmetic number, because the mean of its divisors is an integer number (935683584).

Almost surely, 2^21125033421 is an apocalyptic number.

It is an amenable number.

21125033421 is a deficient number, since it is larger than the sum of its proper divisors (8816841267).

21125033421 is a wasteful number, since it uses less digits than its factorization.

21125033421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33881.

The product of its (nonzero) digits is 1440, while the sum is 24.

Adding to 21125033421 its reverse (12433052112), we get a palindrome (33558085533).

The spelling of 21125033421 in words is "twenty-one billion, one hundred twenty-five million, thirty-three thousand, four hundred twenty-one".