21064263408 has 160 divisors (see below), whose sum is σ = 62553139200. Its totient is φ = 6779635200.

The previous prime is 21064263403. The next prime is 21064263421. The reversal of 21064263408 is 80436246012.

21064263408 is a `hidden beast` number, since 2 + 1 + 0 + 642 + 6 + 3 + 4 + 0 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21064263401) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6975723 + ... + 6978741.

It is an arithmetic number, because the mean of its divisors is an integer number (390957120).

Almost surely, 2^21064263408 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 21064263408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31276569600).

21064263408 is an abundant number, since it is smaller than the sum of its proper divisors (41488875792).

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

21064263408 is a wasteful number, since it uses less digits than its factorization.

21064263408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3588 (or 3576 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 36.

The spelling of 21064263408 in words is "twenty-one billion, sixty-four million, two hundred sixty-three thousand, four hundred eight".