21255214204 has 48 divisors (see below), whose sum is σ = 44591210496. Its totient is φ = 8667648000.

The previous prime is 21255214199. The next prime is 21255214207. The reversal of 21255214204 is 40241255212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21255214207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36604 + ... + 209404.

It is an arithmetic number, because the mean of its divisors is an integer number (928983552).

Almost surely, 2^21255214204 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 21255214204, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22295605248).

21255214204 is an abundant number, since it is smaller than the sum of its proper divisors (23335996292).

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

21255214204 is a wasteful number, since it uses less digits than its factorization.

21255214204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173026 (or 173024 counting only the distinct ones).

The product of its (nonzero) digits is 6400, while the sum is 28.

Adding to 21255214204 its reverse (40241255212), we get a palindrome (61496469416).

The spelling of 21255214204 in words is "twenty-one billion, two hundred fifty-five million, two hundred fourteen thousand, two hundred four".