21064539672 has 128 divisors (see below), whose sum is σ = 63928051200. Its totient is φ = 6373584000.

The previous prime is 21064539667. The next prime is 21064539679. The reversal of 21064539672 is 27693546012.

21064539672 is a `hidden beast` number, since 2 + 106 + 4 + 539 + 6 + 7 + 2 = 666.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21064539679) 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, 1659253 + ... + 1671899.

It is an arithmetic number, because the mean of its divisors is an integer number (499437900).

Almost surely, 2^21064539672 is an apocalyptic number.

21064539672 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21064539672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31964025600).

21064539672 is an abundant number, since it is smaller than the sum of its proper divisors (42863511528).

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

21064539672 is a wasteful number, since it uses less digits than its factorization.

21064539672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13374 (or 13364 counting only the distinct ones).

The product of its (nonzero) digits is 544320, while the sum is 45.

The spelling of 21064539672 in words is "twenty-one billion, sixty-four million, five hundred thirty-nine thousand, six hundred seventy-two".