661017 has 8 divisors (see below), whose sum is σ = 1007296. Its totient is φ = 377712.

The previous prime is 661009. The next prime is 661019. The reversal of 661017 is 710166.

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

It is not a de Polignac number, because 661017 - 2³ = 661009 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 31477 = 661017 / (6 + 6 + 1 + 0 + 1 + 7).

It is a Duffinian number.

It is a nialpdrome in base 7.

It is a junction number, because it is equal to n+sod(n) for n = 660984 and 661002.

It is not an unprimeable number, because it can be changed into a prime (661019) 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, 15718 + ... + 15759.

It is an arithmetic number, because the mean of its divisors is an integer number (125912).

2⁶⁶¹⁰¹⁷ is an apocalyptic number.

It is an amenable number.

661017 is a deficient number, since it is larger than the sum of its proper divisors (346279).

661017 is a wasteful number, since it uses less digits than its factorization.

661017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31487.

The product of its (nonzero) digits is 252, while the sum is 21.

The square root of 661017 is about 813.0295197593. The cubic root of 661017 is about 87.1105741619.

The spelling of 661017 in words is "six hundred sixty-one thousand, seventeen".