21420213124 has 12 divisors (see below), whose sum is σ = 37504328400. Its totient is φ = 10704690728.

The previous prime is 21420213119. The next prime is 21420213137. The reversal of 21420213124 is 42131202412.

It is a junction number, because it is equal to n+sod(n) for n = 21420213095 and 21420213104.

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, 1345054 + ... + 1360885.

It is an arithmetic number, because the mean of its divisors is an integer number (3125360700).

Almost surely, 2^21420213124 is an apocalyptic number.

It is an amenable number.

21420213124 is a deficient number, since it is larger than the sum of its proper divisors (16084115276).

21420213124 is a wasteful number, since it uses less digits than its factorization.

21420213124 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2707922 (or 2707920 counting only the distinct ones).

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

Adding to 21420213124 its reverse (42131202412), we get a palindrome (63551415536).

The spelling of 21420213124 in words is "twenty-one billion, four hundred twenty million, two hundred thirteen thousand, one hundred twenty-four".