666153641556 has 54 divisors (see below), whose sum is σ = 1823382099630. Its totient is φ = 204970349376.

The previous prime is 666153641471. The next prime is 666153641611. The reversal of 666153641556 is 655146351666.

It can be written as a sum of positive squares in 3 ways, for example, as 434722500 + 665718919056 = 20850^2 + 815916^2 .

It is a super-2 number, since 2×666153641556² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 54740271 + ... + 54752438.

Almost surely, 2^666153641556 is an apocalyptic number.

It is an amenable number.

666153641556 is an abundant number, since it is smaller than the sum of its proper divisors (1157228458074).

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

666153641556 is a wasteful number, since it uses less digits than its factorization.

666153641556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109492745 (or 109492727 counting only the distinct ones).

The product of its digits is 11664000, while the sum is 54.

The spelling of 666153641556 in words is "six hundred sixty-six billion, one hundred fifty-three million, six hundred forty-one thousand, five hundred fifty-six".