21013404104 has 128 divisors (see below), whose sum is σ = 49809150720. Its totient is φ = 8073216000.

The previous prime is 21013404029. The next prime is 21013404109. The reversal of 21013404104 is 40140431012.

It is not an unprimeable number, because it can be changed into a prime (21013404109) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 23960114 + ... + 23960990.

It is an arithmetic number, because the mean of its divisors is an integer number (389133990).

Almost surely, 2^21013404104 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 21013404104, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24904575360).

21013404104 is an abundant number, since it is smaller than the sum of its proper divisors (28795746616).

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

21013404104 is a wasteful number, since it uses less digits than its factorization.

21013404104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1399 (or 1395 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

Adding to 21013404104 its reverse (40140431012), we get a palindrome (61153835116).

The spelling of 21013404104 in words is "twenty-one billion, thirteen million, four hundred four thousand, one hundred four".