21064085380 has 96 divisors (see below), whose sum is σ = 49186529280. Its totient is φ = 7527582720.

The previous prime is 21064085353. The next prime is 21064085381. The reversal of 21064085380 is 8358046012.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21064085381) 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 31 ways as a sum of consecutive naturals, for example, 1346041 + ... + 1361599.

It is an arithmetic number, because the mean of its divisors is an integer number (512359680).

Almost surely, 2^21064085380 is an apocalyptic number.

21064085380 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 21064085380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24593264640).

21064085380 is an abundant number, since it is smaller than the sum of its proper divisors (28122443900).

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

21064085380 is a wasteful number, since it uses less digits than its factorization.

21064085380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15749 (or 15747 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 37.

The spelling of 21064085380 in words is "twenty-one billion, sixty-four million, eighty-five thousand, three hundred eighty".