21130124421 has 24 divisors (see below), whose sum is σ = 32789119584. Its totient is φ = 12068511840.

The previous prime is 21130124419. The next prime is 21130124423. The reversal of 21130124421 is 12442103112.

It is an interprime number because it is at equal distance from previous prime (21130124419) and next prime (21130124423).

It is not a de Polignac number, because 21130124421 - 2¹ = 21130124419 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21130124423) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 279531 + ... + 346983.

It is an arithmetic number, because the mean of its divisors is an integer number (1366213316).

Almost surely, 2^21130124421 is an apocalyptic number.

21130124421 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21130124421 is a deficient number, since it is larger than the sum of its proper divisors (11658995163).

21130124421 is a wasteful number, since it uses less digits than its factorization.

21130124421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69601 (or 69594 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

Adding to 21130124421 its reverse (12442103112), we get a palindrome (33572227533).

The spelling of 21130124421 in words is "twenty-one billion, one hundred thirty million, one hundred twenty-four thousand, four hundred twenty-one".