66557422081 has 4 divisors (see below), whose sum is σ = 66587969200. Its totient is φ = 66526874964.

The previous prime is 66557422079. The next prime is 66557422091. The reversal of 66557422081 is 18022475566.

66557422081 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 not a de Polignac number, because 66557422081 - 2¹ = 66557422079 is a prime.

It is a super-2 number, since 2×66557422081² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66557422031) 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, 15270291 + ... + 15274648.

It is an arithmetic number, because the mean of its divisors is an integer number (16646992300).

Almost surely, 2^66557422081 is an apocalyptic number.

It is an amenable number.

66557422081 is a deficient number, since it is larger than the sum of its proper divisors (30547119).

66557422081 is a wasteful number, since it uses less digits than its factorization.

66557422081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30547118.

The product of its (nonzero) digits is 806400, while the sum is 46.

The spelling of 66557422081 in words is "sixty-six billion, five hundred fifty-seven million, four hundred twenty-two thousand, eighty-one".