66040021755 has 48 divisors (see below), whose sum is σ = 115724834784. Its totient is φ = 34836111360.

The previous prime is 66040021753. The next prime is 66040021781. The reversal of 66040021755 is 55712004066.

It is a happy number.

It is not a de Polignac number, because 66040021755 - 2¹ = 66040021753 is a prime.

It is a super-2 number, since 2×66040021755² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66040021753) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3075717 + ... + 3097113.

It is an arithmetic number, because the mean of its divisors is an integer number (2410934058).

Almost surely, 2^66040021755 is an apocalyptic number.

66040021755 is a deficient number, since it is larger than the sum of its proper divisors (49684813029).

66040021755 is a wasteful number, since it uses less digits than its factorization.

66040021755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22156 (or 22153 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 36.

The spelling of 66040021755 in words is "sixty-six billion, forty million, twenty-one thousand, seven hundred fifty-five".