21064597884 has 192 divisors, whose sum is σ = 60570316800. Its totient is φ = 6355946880.

The previous prime is 21064597849. The next prime is 21064597889. The reversal of 21064597884 is 48879546012.

It is a happy number.

21064597884 is a `hidden beast` number, since 2 + 106 + 459 + 7 + 8 + 84 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 21064597884.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21064597889) 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 63 ways as a sum of consecutive naturals, for example, 43975957 + ... + 43976435.

It is an arithmetic number, because the mean of its divisors is an integer number (315470400).

Almost surely, 2^21064597884 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 21064597884, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30285158400).

21064597884 is an abundant number, since it is smaller than the sum of its proper divisors (39505718916).

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

21064597884 is a wasteful number, since it uses less digits than its factorization.

21064597884 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 972 (or 952 counting only the distinct ones).

The product of its (nonzero) digits is 3870720, while the sum is 54.

The spelling of 21064597884 in words is "twenty-one billion, sixty-four million, five hundred ninety-seven thousand, eight hundred eighty-four".