666061655 has 24 divisors (see below), whose sum is σ = 939386448. Its totient is φ = 452003328.

The previous prime is 666061651. The next prime is 666061657. The reversal of 666061655 is 556160666.

It is not a de Polignac number, because 666061655 - 2² = 666061651 is a prime.

It is a super-2 number, since 2×666061655² = 887276256522678050, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666061651) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9752 + ... + 37778.

It is an arithmetic number, because the mean of its divisors is an integer number (39141102).

Almost surely, 2^666061655 is an apocalyptic number.

666061655 is a deficient number, since it is larger than the sum of its proper divisors (273324793).

666061655 is a wasteful number, since it uses less digits than its factorization.

666061655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28143 (or 28136 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 41.

The square root of 666061655 is about 25808.1703148441. The cubic root of 666061655 is about 873.3161215683.

The spelling of 666061655 in words is "six hundred sixty-six million, sixty-one thousand, six hundred fifty-five".