21225149565984 has 768 divisors, whose sum is σ = 78906392248320. Its totient is φ = 5399654400000.

The previous prime is 21225149565973. The next prime is 21225149566009. The reversal of 21225149565984 is 48956594152212.

It is a happy number.

21225149565984 is a `hidden beast` number, since 2 + 1 + 2 + 2 + 5 + 1 + 495 + 65 + 9 + 84 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 757999984 + ... + 758027984.

It is an arithmetic number, because the mean of its divisors is an integer number (102742698240).

Almost surely, 2^{21225149565984} is an apocalyptic number.

21225149565984 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 21225149565984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39453196124160).

21225149565984 is an abundant number, since it is smaller than the sum of its proper divisors (57681242682336).

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

21225149565984 is a wasteful number, since it uses less digits than its factorization.

21225149565984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28382 (or 28368 counting only the distinct ones).

The product of its digits is 62208000, while the sum is 63.

The spelling of 21225149565984 in words is "twenty-one trillion, two hundred twenty-five billion, one hundred forty-nine million, five hundred sixty-five thousand, nine hundred eighty-four".