21405873392640 has 1056 divisors, whose sum is σ = 83884950100224. Its totient is φ = 5001394913280.

The previous prime is 21405873392599. The next prime is 21405873392699. The reversal of 21405873392640 is 4629337850412.

21405873392640 is a `hidden beast` number, since 2 + 1 + 4 + 0 + 587 + 3 + 39 + 26 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1056).

It is a super-2 number, since 2×21405873392640² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2006732587 + ... + 2006743253.

It is a 1-persistent number, because it is pandigital, but 2⋅21405873392640 = 42811746785280 is not.

Almost surely, 2^{21405873392640} is an apocalyptic number.

21405873392640 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 21405873392640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41942475050112).

21405873392640 is an abundant number, since it is smaller than the sum of its proper divisors (62479076707584).

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

21405873392640 is a wasteful number, since it uses less digits than its factorization.

21405873392640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10853 (or 10832 counting only the distinct ones).

The product of its (nonzero) digits is 8709120, while the sum is 54.

The spelling of 21405873392640 in words is "twenty-one trillion, four hundred five billion, eight hundred seventy-three million, three hundred ninety-two thousand, six hundred forty".