661161101 has 4 divisors (see below), whose sum is σ = 661288572. Its totient is φ = 661033632.

The previous prime is 661161097. The next prime is 661161113. The reversal of 661161101 is 101161166.

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

It can be written as a sum of positive squares in 2 ways, for example, as 42445225 + 618715876 = 6515^2 + 24874^2 .

It is a cyclic number.

It is not a de Polignac number, because 661161101 - 2² = 661161097 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661161131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55610 + ... + 66443.

It is an arithmetic number, because the mean of its divisors is an integer number (165322143).

Almost surely, 2^661161101 is an apocalyptic number.

It is an amenable number.

661161101 is a deficient number, since it is larger than the sum of its proper divisors (127471).

661161101 is a wasteful number, since it uses less digits than its factorization.

661161101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127470.

The product of its (nonzero) digits is 216, while the sum is 23.

The square root of 661161101 is about 25713.0531248236. The cubic root of 661161101 is about 871.1690370599.

The spelling of 661161101 in words is "six hundred sixty-one million, one hundred sixty-one thousand, one hundred one".