21405066415 has 12 divisors (see below), whose sum is σ = 26244233496. Its totient is φ = 16759702928.

The previous prime is 21405066407. The next prime is 21405066421. The reversal of 21405066415 is 51466050412.

It is not a de Polignac number, because 21405066415 - 2³ = 21405066407 is a prime.

It is a Duffinian number.

It is a congruent number.

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 11 ways as a sum of consecutive naturals, for example, 957949 + ... + 980038.

It is an arithmetic number, because the mean of its divisors is an integer number (2187019458).

Almost surely, 2^21405066415 is an apocalyptic number.

21405066415 is a deficient number, since it is larger than the sum of its proper divisors (4839167081).

21405066415 is an equidigital number, since it uses as much as digits as its factorization.

21405066415 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1938086 (or 1938039 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 34.

The spelling of 21405066415 in words is "twenty-one billion, four hundred five million, sixty-six thousand, four hundred fifteen".