661656061 has 8 divisors (see below), whose sum is σ = 722527200. Its totient is φ = 600905040.

The previous prime is 661656053. The next prime is 661656071. The reversal of 661656061 is 160656166.

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

It is a cyclic number.

It is not a de Polignac number, because 661656061 - 2³ = 661656053 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 661656061.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661656001) 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, 18306 + ... + 40723.

It is an arithmetic number, because the mean of its divisors is an integer number (90315900).

Almost surely, 2^661656061 is an apocalyptic number.

It is an amenable number.

661656061 is a deficient number, since it is larger than the sum of its proper divisors (60871139).

661656061 is a wasteful number, since it uses less digits than its factorization.

661656061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60059.

The product of its (nonzero) digits is 38880, while the sum is 37.

The square root of 661656061 is about 25722.6760077563. The cubic root of 661656061 is about 871.3863750482.

The spelling of 661656061 in words is "six hundred sixty-one million, six hundred fifty-six thousand, sixty-one".