21420532404505 has 8 divisors (see below), whose sum is σ = 27681918799752. Its totient is φ = 15818239314048.

The previous prime is 21420532404449. The next prime is 21420532404539. The reversal of 21420532404505 is 50540423502412.

It can be written as a sum of positive squares in 4 ways, for example, as 102098142784 + 21318434261721 = 319528^2 + 4617189^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21420532404505 - 2⁷ = 21420532404377 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 164773326124 + ... + 164773326253.

It is an arithmetic number, because the mean of its divisors is an integer number (3460239849969).

Almost surely, 2^{21420532404505} is an apocalyptic number.

It is an amenable number.

21420532404505 is a deficient number, since it is larger than the sum of its proper divisors (6261386395247).

21420532404505 is a wasteful number, since it uses less digits than its factorization.

21420532404505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 329546652395.

The product of its (nonzero) digits is 192000, while the sum is 37.

Adding to 21420532404505 its reverse (50540423502412), we get a palindrome (71960955906917).

The spelling of 21420532404505 in words is "twenty-one trillion, four hundred twenty billion, five hundred thirty-two million, four hundred four thousand, five hundred five".