665154451566 has 32 divisors (see below), whose sum is σ = 1612495641600. Its totient is φ = 201561954840.

The previous prime is 665154451561. The next prime is 665154451567.

665154451566 is a `hidden beast` number, since 6 + 65 + 1 + 5 + 4 + 4 + 515 + 66 = 666.

665154451566 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665154451561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 559893726 + ... + 559894913.

It is an arithmetic number, because the mean of its divisors is an integer number (50390488800).

Almost surely, 2^665154451566 is an apocalyptic number.

665154451566 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

665154451566 is an abundant number, since it is smaller than the sum of its proper divisors (947341190034).

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

665154451566 is a wasteful number, since it uses less digits than its factorization.

665154451566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1119788661 (or 1119788655 counting only the distinct ones).

The product of its digits is 12960000, while the sum is 54.

The spelling of 665154451566 in words is "six hundred sixty-five billion, one hundred fifty-four million, four hundred fifty-one thousand, five hundred sixty-six".