21004205530 has 128 divisors (see below), whose sum is σ = 48306585600. Its totient is φ = 6385271040.

The previous prime is 21004205513. The next prime is 21004205569. The reversal of 21004205530 is 3550240012.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 12629479 + ... + 12631141.

It is an arithmetic number, because the mean of its divisors is an integer number (377395200).

Almost surely, 2^21004205530 is an apocalyptic number.

21004205530 is an abundant number, since it is smaller than the sum of its proper divisors (27302380070).

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

21004205530 is a wasteful number, since it uses less digits than its factorization.

21004205530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2084.

The product of its (nonzero) digits is 1200, while the sum is 22.

Adding to 21004205530 its reverse (3550240012), we get a palindrome (24554445542).

The spelling of 21004205530 in words is "twenty-one billion, four million, two hundred five thousand, five hundred thirty".