21613240721016 has 192 divisors, whose sum is σ = 68279336985600. Its totient is φ = 6048562464000.

The previous prime is 21613240720993. The next prime is 21613240721047. The reversal of 21613240721016 is 61012704231612.

21613240721016 is a `hidden beast` number, since 2 + 1 + 6 + 1 + 32 + 407 + 210 + 1 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5877091 + ... + 8818541.

It is an arithmetic number, because the mean of its divisors is an integer number (355621546800).

Almost surely, 2^{21613240721016} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21613240721016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34139668492800).

21613240721016 is an abundant number, since it is smaller than the sum of its proper divisors (46666096264584).

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

21613240721016 is a wasteful number, since it uses less digits than its factorization.

21613240721016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2941770 (or 2941763 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

Adding to 21613240721016 its reverse (61012704231612), we get a palindrome (82625944952628).

The spelling of 21613240721016 in words is "twenty-one trillion, six hundred thirteen billion, two hundred forty million, seven hundred twenty-one thousand, sixteen".