661142056 has 16 divisors (see below), whose sum is σ = 1269877140. Its totient is φ = 322508160.

The previous prime is 661142051. The next prime is 661142081. The reversal of 661142056 is 650241166.

It can be written as a sum of positive squares in 2 ways, for example, as 657101956 + 4040100 = 25634^2 + 2010^2 .

It is not an unprimeable number, because it can be changed into a prime (661142051) 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, 1007511 + ... + 1008166.

Almost surely, 2^661142056 is an apocalyptic number.

It is an amenable number.

661142056 is a deficient number, since it is larger than the sum of its proper divisors (608735084).

661142056 is a wasteful number, since it uses less digits than its factorization.

661142056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2015724 (or 2015720 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 661142056 is about 25712.6827849604. The cubic root of 661142056 is about 871.1606721931.

The spelling of 661142056 in words is "six hundred sixty-one million, one hundred forty-two thousand, fifty-six".