661106550655 has 4 divisors (see below), whose sum is σ = 793327860792. Its totient is φ = 528885240520.

The previous prime is 661106550619. The next prime is 661106550677. The reversal of 661106550655 is 556055601166.

It is a semiprime because it is the product of two primes.

It is a de Polignac number, because none of the positive numbers 2^k-661106550655 is a prime.

It is a super-3 number, since 3×661106550655³ (a number of 36 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66110655061 + ... + 66110655070.

It is an arithmetic number, because the mean of its divisors is an integer number (198331965198).

Almost surely, 2^661106550655 is an apocalyptic number.

661106550655 is a deficient number, since it is larger than the sum of its proper divisors (132221310137).

661106550655 is a wasteful number, since it uses less digits than its factorization.

661106550655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132221310136.

The product of its (nonzero) digits is 810000, while the sum is 46.

The spelling of 661106550655 in words is "six hundred sixty-one billion, one hundred six million, five hundred fifty thousand, six hundred fifty-five".