21545147520 has 288 divisors, whose sum is σ = 80564882580. Its totient is φ = 5303181312.

The previous prime is 21545147513. The next prime is 21545147633. The reversal of 21545147520 is 2574154512.

21545147520 is a `hidden beast` number, since 2 + 1 + 54 + 514 + 75 + 20 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 2081549376 + 19463598144 = 45624^2 + 139512^2 .

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

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 962374 + ... + 984506.

Almost surely, 2^21545147520 is an apocalyptic number.

21545147520 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 21545147520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40282441290).

21545147520 is an abundant number, since it is smaller than the sum of its proper divisors (59019735060).

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

21545147520 is a wasteful number, since it uses less digits than its factorization.

21545147520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22184 (or 22156 counting only the distinct ones).

The product of its (nonzero) digits is 56000, while the sum is 36.

The spelling of 21545147520 in words is "twenty-one billion, five hundred forty-five million, one hundred forty-seven thousand, five hundred twenty".