661118642 has 16 divisors (see below), whose sum is σ = 1044822240. Its totient is φ = 312876288.

The previous prime is 661118641. The next prime is 661118651. The reversal of 661118642 is 246811166.

It is not an unprimeable number, because it can be changed into a prime (661118641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37778 + ... + 52434.

It is an arithmetic number, because the mean of its divisors is an integer number (65301390).

Almost surely, 2^661118642 is an apocalyptic number.

661118642 is a deficient number, since it is larger than the sum of its proper divisors (383703598).

661118642 is a wasteful number, since it uses less digits than its factorization.

661118642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15865.

The product of its digits is 13824, while the sum is 35.

The square root of 661118642 is about 25712.2274803254. The cubic root of 661118642 is about 871.1503881719.

The spelling of 661118642 in words is "six hundred sixty-one million, one hundred eighteen thousand, six hundred forty-two".