661143065 has 16 divisors (see below), whose sum is σ = 865995840. Its totient is φ = 480553920.

The previous prime is 661143023. The next prime is 661143083. The reversal of 661143065 is 560341166.

661143065 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 661143065 - 2⁶ = 661143001 is a prime.

It is a super-2 number, since 2×661143065² = 874220304795188450, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 184622 + ... + 188168.

It is an arithmetic number, because the mean of its divisors is an integer number (54124740).

Almost surely, 2^661143065 is an apocalyptic number.

It is an amenable number.

661143065 is a deficient number, since it is larger than the sum of its proper divisors (204852775).

661143065 is a wasteful number, since it uses less digits than its factorization.

661143065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6952.

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 661143065 is about 25712.7024056205. The cubic root of 661143065 is about 871.1611153660.

The spelling of 661143065 in words is "six hundred sixty-one million, one hundred forty-three thousand, sixty-five".