155665666 has 8 divisors (see below), whose sum is σ = 251459964. Its totient is φ = 71845680.

The previous prime is 155665661. The next prime is 155665667. The reversal of 155665666 is 666566551.

It can be written as a sum of positive squares in 2 ways, for example, as 151167025 + 4498641 = 12295^2 + 2121^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (155665661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2993545 + ... + 2993596.

Almost surely, 2^155665666 is an apocalyptic number.

155665666 is a deficient number, since it is larger than the sum of its proper divisors (95794298).

155665666 is a wasteful number, since it uses less digits than its factorization.

155665666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5987156.

The product of its digits is 972000, while the sum is 46.

The square root of 155665666 is about 12476.6047464845. The cubic root of 155665666 is about 537.9364154204.

The spelling of 155665666 in words is "one hundred fifty-five million, six hundred sixty-five thousand, six hundred sixty-six".