21064135680 has 792 divisors, whose sum is σ = 89553466080. Its totient is φ = 4551966720.

The previous prime is 21064135679. The next prime is 21064135681. The reversal of 21064135680 is 8653146012.

It is a happy number.

21064135680 is a `hidden beast` number, since 2 + 1 + 0 + 641 + 3 + 5 + 6 + 8 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (21064135679) and next prime (21064135681).

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 (21064135681) 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 71 ways as a sum of consecutive naturals, for example, 42900235 + ... + 42900725.

Almost surely, 2^21064135680 is an apocalyptic number.

21064135680 is a gapful number since it is divisible by the number (20) 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 21064135680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44776733040).

21064135680 is an abundant number, since it is smaller than the sum of its proper divisors (68489330400).

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

21064135680 is a wasteful number, since it uses less digits than its factorization.

21064135680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 555 (or 527 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The spelling of 21064135680 in words is "twenty-one billion, sixty-four million, one hundred thirty-five thousand, six hundred eighty".