21615404016320 has 28 divisors (see below), whose sum is σ = 51471680814624. Its totient is φ = 8646161606400.

The previous prime is 21615404016301. The next prime is 21615404016341. The reversal of 21615404016320 is 2361040451612.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33774068456 + ... + 33774069095.

It is an arithmetic number, because the mean of its divisors is an integer number (1838274314808).

Almost surely, 2^{21615404016320} is an apocalyptic number.

21615404016320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21615404016320 is an abundant number, since it is smaller than the sum of its proper divisors (29856276798304).

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

21615404016320 is an equidigital number, since it uses as much as digits as its factorization.

21615404016320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67548137568 (or 67548137558 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 35.

Adding to 21615404016320 its reverse (2361040451612), we get a palindrome (23976444467932).

The spelling of 21615404016320 in words is "twenty-one trillion, six hundred fifteen billion, four hundred four million, sixteen thousand, three hundred twenty".