21420273204 has 96 divisors (see below), whose sum is σ = 60613217280. Its totient is φ = 6487711200.

The previous prime is 21420273169. The next prime is 21420273253. The reversal of 21420273204 is 40237202412.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3445659 + ... + 3451869.

It is an arithmetic number, because the mean of its divisors is an integer number (631387680).

Almost surely, 2^21420273204 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21420273204, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30306608640).

21420273204 is an abundant number, since it is smaller than the sum of its proper divisors (39192944076).

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

21420273204 is a wasteful number, since it uses less digits than its factorization.

21420273204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9138 (or 9130 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 27.

Adding to 21420273204 its reverse (40237202412), we get a palindrome (61657475616).

The spelling of 21420273204 in words is "twenty-one billion, four hundred twenty million, two hundred seventy-three thousand, two hundred four".