661101 has 8 divisors (see below), whose sum is σ = 1007424. Its totient is φ = 377760.

The previous prime is 661099. The next prime is 661103. The reversal of 661101 is 101166.

661101 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (661099) and next prime (661103).

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

It is not a de Polignac number, because 661101 - 2¹ = 661099 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661103) 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, 15720 + ... + 15761.

It is an arithmetic number, because the mean of its divisors is an integer number (125928).

2⁶⁶¹¹⁰¹ is an apocalyptic number.

It is an amenable number.

661101 is a deficient number, since it is larger than the sum of its proper divisors (346323).

661101 is a wasteful number, since it uses less digits than its factorization.

661101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31491.

The product of its (nonzero) digits is 36, while the sum is 15.

The square root of 661101 is about 813.0811767591. The cubic root of 661101 is about 87.1142639199.

Adding to 661101 its reverse (101166), we get a palindrome (762267).

The spelling of 661101 in words is "six hundred sixty-one thousand, one hundred one".