660640641 has 8 divisors (see below), whose sum is σ = 895784160. Its totient is φ = 432962112.

The previous prime is 660640637. The next prime is 660640709. The reversal of 660640641 is 146046066.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 660640641 - 2² = 660640637 is a prime.

It is not an unprimeable number, because it can be changed into a prime (660642641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1866040 + ... + 1866393.

It is an arithmetic number, because the mean of its divisors is an integer number (111973020).

Almost surely, 2^660640641 is an apocalyptic number.

It is an amenable number.

660640641 is a deficient number, since it is larger than the sum of its proper divisors (235143519).

660640641 is a wasteful number, since it uses less digits than its factorization.

660640641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3732495.

The product of its (nonzero) digits is 20736, while the sum is 33.

The square root of 660640641 is about 25702.9305916660. The cubic root of 660640641 is about 870.9403849400.

The spelling of 660640641 in words is "six hundred sixty million, six hundred forty thousand, six hundred forty-one".