21204681732 has 144 divisors (see below), whose sum is σ = 60455111808. Its totient is φ = 6217896960.

The previous prime is 21204681661. The next prime is 21204681733. The reversal of 21204681732 is 23718640212.

It is a happy number.

21204681732 is a `hidden beast` number, since 2 + 1 + 20 + 468 + 173 + 2 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (21204681733) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 3042732 + ... + 3049692.

Almost surely, 2^21204681732 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 21204681732, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30227555904).

21204681732 is an abundant number, since it is smaller than the sum of its proper divisors (39250430076).

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

21204681732 is a wasteful number, since it uses less digits than its factorization.

21204681732 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7290 (or 7285 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The spelling of 21204681732 in words is "twenty-one billion, two hundred four million, six hundred eighty-one thousand, seven hundred thirty-two".