21520553040 has 300 divisors, whose sum is σ = 86948465076. Its totient is φ = 4918910976.

The previous prime is 21520552973. The next prime is 21520553101. The reversal of 21520553040 is 4035502512.

It is a happy number.

21520553040 is a `hidden beast` number, since 21 + 52 + 0 + 553 + 0 + 40 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 11309046336 + 10211506704 = 106344^2 + 101052^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 21520552995 and 21520553013.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 283632 + ... + 351408.

Almost surely, 2^21520553040 is an apocalyptic number.

21520553040 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 21520553040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43474232538).

21520553040 is an abundant number, since it is smaller than the sum of its proper divisors (65427912036).

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

21520553040 is a wasteful number, since it uses less digits than its factorization.

21520553040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67816 (or 67794 counting only the distinct ones).

The product of its (nonzero) digits is 6000, while the sum is 27.

The spelling of 21520553040 in words is "twenty-one billion, five hundred twenty million, five hundred fifty-three thousand, forty".