21405410347321 has 48 divisors (see below), whose sum is σ = 29378901097728. Its totient is φ = 15330418387200.

The previous prime is 21405410347273. The next prime is 21405410347327. The reversal of 21405410347321 is 12374301450412.

It is not a de Polignac number, because 21405410347321 - 2¹⁷ = 21405410216249 is a prime.

It is a super-3 number, since 3×21405410347321³ (a number of 41 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21405410347327) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4922865 + ... + 8188126.

It is an arithmetic number, because the mean of its divisors is an integer number (612060439536).

Almost surely, 2^{21405410347321} is an apocalyptic number.

It is an amenable number.

21405410347321 is a deficient number, since it is larger than the sum of its proper divisors (7973490750407).

21405410347321 is a wasteful number, since it uses less digits than its factorization.

21405410347321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13111262 (or 13111255 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 37.

Adding to 21405410347321 its reverse (12374301450412), we get a palindrome (33779711797733).

The spelling of 21405410347321 in words is "twenty-one trillion, four hundred five billion, four hundred ten million, three hundred forty-seven thousand, three hundred twenty-one".