66280155781 has 32 divisors (see below), whose sum is σ = 81805137408. Its totient is φ = 52404817920.

The previous prime is 66280155751. The next prime is 66280155787. The reversal of 66280155781 is 18755108266.

It is not a de Polignac number, because 66280155781 - 2⁵ = 66280155749 is a prime.

It is a super-2 number, since 2×66280155781² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66280155787) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6497421 + ... + 6507613.

It is an arithmetic number, because the mean of its divisors is an integer number (2556410544).

Almost surely, 2^66280155781 is an apocalyptic number.

It is an amenable number.

66280155781 is a deficient number, since it is larger than the sum of its proper divisors (15524981627).

66280155781 is a wasteful number, since it uses less digits than its factorization.

66280155781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11301.

The product of its (nonzero) digits is 806400, while the sum is 49.

The spelling of 66280155781 in words is "sixty-six billion, two hundred eighty million, one hundred fifty-five thousand, seven hundred eighty-one".