21007516064 has 24 divisors (see below), whose sum is σ = 41398418880. Its totient is φ = 10493631936.

The previous prime is 21007516039. The next prime is 21007516067. The reversal of 21007516064 is 46061570012.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a self number, because there is not a number n which added to its sum of digits gives 21007516064.

It is not an unprimeable number, because it can be changed into a prime (21007516067) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 282674 + ... + 349169.

It is an arithmetic number, because the mean of its divisors is an integer number (1724934120).

Almost surely, 2^21007516064 is an apocalyptic number.

It is an amenable number.

21007516064 is a deficient number, since it is larger than the sum of its proper divisors (20390902816).

21007516064 is a wasteful number, since it uses less digits than its factorization.

21007516064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 632892 (or 632884 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 32.

The spelling of 21007516064 in words is "twenty-one billion, seven million, five hundred sixteen thousand, sixty-four".