661347760 has 40 divisors (see below), whose sum is σ = 1540030896. Its totient is φ = 264126720.

The previous prime is 661347737. The next prime is 661347761. The reversal of 661347760 is 67743166.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (661347761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48055 + ... + 60265.

Almost surely, 2^661347760 is an apocalyptic number.

It is an amenable number.

661347760 is an abundant number, since it is smaller than the sum of its proper divisors (878683136).

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

661347760 is a wasteful number, since it uses less digits than its factorization.

661347760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12901 (or 12895 counting only the distinct ones).

The product of its (nonzero) digits is 127008, while the sum is 40.

The square root of 661347760 is about 25716.6825232183. The cubic root of 661347760 is about 871.2510121593.

The spelling of 661347760 in words is "six hundred sixty-one million, three hundred forty-seven thousand, seven hundred sixty".