21432176640 has 832 divisors, whose sum is σ = 89642304000. Its totient is φ = 4855431168.

The previous prime is 21432176627. The next prime is 21432176651. The reversal of 21432176640 is 4667123412.

21432176640 is a `hidden beast` number, since 2 + 1 + 4 + 3 + 2 + 1 + 7 + 6 + 640 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 21432176595 and 21432176604.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 189665224 + ... + 189665336.

Almost surely, 2^21432176640 is an apocalyptic number.

21432176640 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 21432176640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44821152000).

21432176640 is an abundant number, since it is smaller than the sum of its proper divisors (68210127360).

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

21432176640 is an equidigital number, since it uses as much as digits as its factorization.

21432176640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172 (or 130 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 36.

The spelling of 21432176640 in words is "twenty-one billion, four hundred thirty-two million, one hundred seventy-six thousand, six hundred forty".