665155551666 has 16 divisors (see below), whose sum is σ = 1332674007264. Its totient is φ = 221324699904.

The previous prime is 665155551659. The next prime is 665155551673. The reversal of 665155551666 is 666155551566.

665155551666 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (665155551659) and next prime (665155551673).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 98450671 + ... + 98457426.

It is an arithmetic number, because the mean of its divisors is an integer number (83292125454).

Almost surely, 2^665155551666 is an apocalyptic number.

665155551666 is an abundant number, since it is smaller than the sum of its proper divisors (667518455598).

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

665155551666 is a wasteful number, since it uses less digits than its factorization.

665155551666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196908665.

The product of its digits is 24300000, while the sum is 57.

The spelling of 665155551666 in words is "six hundred sixty-five billion, one hundred fifty-five million, five hundred fifty-one thousand, six hundred sixty-six".