661165061 has 8 divisors (see below), whose sum is σ = 690877824. Its totient is φ = 631532880.

The previous prime is 661165019. The next prime is 661165073. The reversal of 661165061 is 160561166.

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 661165061 - 2¹⁰ = 661164037 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661165081) 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, 3050 + ... + 36491.

It is an arithmetic number, because the mean of its divisors is an integer number (86359728).

Almost surely, 2^661165061 is an apocalyptic number.

It is an amenable number.

661165061 is a deficient number, since it is larger than the sum of its proper divisors (29712763).

661165061 is a wasteful number, since it uses less digits than its factorization.

661165061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40291.

The product of its (nonzero) digits is 6480, while the sum is 32.

The square root of 661165061 is about 25713.1301283994. The cubic root of 661165061 is about 871.1707763347.

The spelling of 661165061 in words is "six hundred sixty-one million, one hundred sixty-five thousand, sixty-one".