66421261321 has 16 divisors (see below), whose sum is σ = 73364659200. Its totient is φ = 59853193488.

The previous prime is 66421261301. The next prime is 66421261393. The reversal of 66421261321 is 12316212466.

It is a cyclic number.

It is not a de Polignac number, because 66421261321 - 2¹⁵ = 66421228553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66421261301) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 346341 + ... + 502786.

It is an arithmetic number, because the mean of its divisors is an integer number (4585291200).

Almost surely, 2^66421261321 is an apocalyptic number.

It is an amenable number.

66421261321 is a deficient number, since it is larger than the sum of its proper divisors (6943397879).

66421261321 is a wasteful number, since it uses less digits than its factorization.

66421261321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 849348.

The product of its digits is 20736, while the sum is 34.

Adding to 66421261321 its reverse (12316212466), we get a palindrome (78737473787).

The spelling of 66421261321 in words is "sixty-six billion, four hundred twenty-one million, two hundred sixty-one thousand, three hundred twenty-one".