21079880640 has 896 divisors, whose sum is σ = 92936202240. Its totient is φ = 4434186240.

The previous prime is 21079880621. The next prime is 21079880651. The reversal of 21079880640 is 4608897012.

It is a super-2 number, since 2×21079880640² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

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 127 ways as a sum of consecutive naturals, for example, 63685275 + ... + 63685605.

It is an arithmetic number, because the mean of its divisors is an integer number (103723440).

Almost surely, 2^21079880640 is an apocalyptic number.

21079880640 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 21079880640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46468101120).

21079880640 is an abundant number, since it is smaller than the sum of its proper divisors (71856321600).

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

21079880640 is an equidigital number, since it uses as much as digits as its factorization.

21079880640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 389 (or 361 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The spelling of 21079880640 in words is "twenty-one billion, seventy-nine million, eight hundred eighty thousand, six hundred forty".