21520035072 has 288 divisors, whose sum is σ = 67700223360. Its totient is φ = 6719569920.

The previous prime is 21520035013. The next prime is 21520035179. The reversal of 21520035072 is 27053002512.

21520035072 is a `hidden beast` number, since 2 + 152 + 0 + 0 + 3 + 507 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a super-2 number, since 2×21520035072² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 43828747 + ... + 43829237.

It is an arithmetic number, because the mean of its divisors is an integer number (235070220).

Almost surely, 2^21520035072 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 21520035072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33850111680).

21520035072 is an abundant number, since it is smaller than the sum of its proper divisors (46180188288).

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

21520035072 is a wasteful number, since it uses less digits than its factorization.

21520035072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 906 (or 886 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 27.

Adding to 21520035072 its reverse (27053002512), we get a palindrome (48573037584).

The spelling of 21520035072 in words is "twenty-one billion, five hundred twenty million, thirty-five thousand, seventy-two".