21213520064 has 112 divisors (see below), whose sum is σ = 49133760000. Its totient is φ = 8984908800.

The previous prime is 21213520063. The next prime is 21213520073. The reversal of 21213520064 is 46002531212.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21213520061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 802937 + ... + 828935.

Almost surely, 2^21213520064 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 21213520064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24566880000).

21213520064 is an abundant number, since it is smaller than the sum of its proper divisors (27920239936).

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

21213520064 is a wasteful number, since it uses less digits than its factorization.

21213520064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26102 (or 26092 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 26.

The spelling of 21213520064 in words is "twenty-one billion, two hundred thirteen million, five hundred twenty thousand, sixty-four".