21000434084 has 96 divisors (see below), whose sum is σ = 45600952320. Its totient is φ = 8256471552.

The previous prime is 21000434053. The next prime is 21000434087. The reversal of 21000434084 is 48043400012.

It is not an unprimeable number, because it can be changed into a prime (21000434087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14715779 + ... + 14717205.

It is an arithmetic number, because the mean of its divisors is an integer number (475009920).

Almost surely, 2^21000434084 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 21000434084, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22800476160).

21000434084 is an abundant number, since it is smaller than the sum of its proper divisors (24600518236).

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

21000434084 is a wasteful number, since it uses less digits than its factorization.

21000434084 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2217 (or 2215 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 26.

Adding to 21000434084 its reverse (48043400012), we get a palindrome (69043834096).

The spelling of 21000434084 in words is "twenty-one billion, four hundred thirty-four thousand, eighty-four".