667644053340726 has 320 divisors, whose sum is σ = 2060744246922240. Its totient is φ = 156116986122240.

The previous prime is 667644053340721. The next prime is 667644053340751. The reversal of 667644053340726 is 627043350446766.

667644053340726 is a `hidden beast` number, since 6 + 6 + 76 + 4 + 4 + 0 + 533 + 4 + 0 + 7 + 26 = 666.

It is a super-2 number, since 2×667644053340726² (a number of 30 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667644053340721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 63566211 + ... + 73320878.

It is an arithmetic number, because the mean of its divisors is an integer number (6439825771632).

Almost surely, 2^{667644053340726} is an apocalyptic number.

667644053340726 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

667644053340726 is an abundant number, since it is smaller than the sum of its proper divisors (1393100193581514).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

667644053340726 is a wasteful number, since it uses less digits than its factorization.

667644053340726 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136887161 (or 136887152 counting only the distinct ones).

The product of its (nonzero) digits is 365783040, while the sum is 63.

The spelling of 667644053340726 in words is "six hundred sixty-seven trillion, six hundred forty-four billion, fifty-three million, three hundred forty thousand, seven hundred twenty-six".