21128613064 has 64 divisors (see below), whose sum is σ = 45529344000. Its totient is φ = 9105675264.

The previous prime is 21128613043. The next prime is 21128613131. The reversal of 21128613064 is 46031682112.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 177487 + ... + 271585.

It is an arithmetic number, because the mean of its divisors is an integer number (711396000).

Almost surely, 2^21128613064 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 21128613064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22764672000).

21128613064 is an abundant number, since it is smaller than the sum of its proper divisors (24400730936).

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

21128613064 is a wasteful number, since it uses less digits than its factorization.

21128613064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94262 (or 94258 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 34.

The spelling of 21128613064 in words is "twenty-one billion, one hundred twenty-eight million, six hundred thirteen thousand, sixty-four".