66026256521 has 4 divisors (see below), whose sum is σ = 66862032000. Its totient is φ = 65190481044.

The previous prime is 66026256511. The next prime is 66026256547. The reversal of 66026256521 is 12565262066.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66026256521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66026256511) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 417887621 + ... + 417887778.

It is an arithmetic number, because the mean of its divisors is an integer number (16715508000).

Almost surely, 2^66026256521 is an apocalyptic number.

It is an amenable number.

66026256521 is a deficient number, since it is larger than the sum of its proper divisors (835775479).

66026256521 is an equidigital number, since it uses as much as digits as its factorization.

66026256521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 835775478.

The product of its (nonzero) digits is 259200, while the sum is 41.

The spelling of 66026256521 in words is "sixty-six billion, twenty-six million, two hundred fifty-six thousand, five hundred twenty-one".