21404528640 has 1248 divisors, whose sum is σ = 92737322496. Its totient is φ = 4671406080.

The previous prime is 21404528599. The next prime is 21404528671. The reversal of 21404528640 is 4682540412.

21404528640 is a `hidden beast` number, since 2 + 1 + 4 + 0 + 4 + 5 + 2 + 8 + 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 = 21404528595 and 21404528604.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 930631669 + ... + 930631691.

It is an arithmetic number, because the mean of its divisors is an integer number (74308752).

Almost surely, 2^21404528640 is an apocalyptic number.

21404528640 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 21404528640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46368661248).

21404528640 is an abundant number, since it is smaller than the sum of its proper divisors (71332793856).

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

21404528640 is a wasteful number, since it uses less digits than its factorization.

21404528640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95 (or 61 counting only the distinct ones).

The product of its (nonzero) digits is 61440, while the sum is 36.

The spelling of 21404528640 in words is "twenty-one billion, four hundred four million, five hundred twenty-eight thousand, six hundred forty".