21552531264 has 336 divisors, whose sum is σ = 70045088256. Its totient is φ = 6277017600.

The previous prime is 21552531139. The next prime is 21552531277. The reversal of 21552531264 is 46213525512.

21552531264 is a `hidden beast` number, since 2 + 1 + 5 + 525 + 3 + 126 + 4 = 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 pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 38693674 + ... + 38694230.

Almost surely, 2^21552531264 is an apocalyptic number.

21552531264 is a gapful number since it is divisible by the number (24) 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 21552531264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35022544128).

21552531264 is an abundant number, since it is smaller than the sum of its proper divisors (48492556992).

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

21552531264 is a wasteful number, since it uses less digits than its factorization.

21552531264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 814 (or 801 counting only the distinct ones).

The product of its digits is 72000, while the sum is 36.

The spelling of 21552531264 in words is "twenty-one billion, five hundred fifty-two million, five hundred thirty-one thousand, two hundred sixty-four".