2017661 has 4 divisors (see below), whose sum is σ = 2028000. Its totient is φ = 2007324.

The previous prime is 2017643. The next prime is 2017669. The reversal of 2017661 is 1667102.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2017661 - 2¹⁸ = 1755517 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2017669) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4871 + ... + 5268.

It is an arithmetic number, because the mean of its divisors is an integer number (507000).

2^2017661 is an apocalyptic number.

It is an amenable number.

2017661 is a deficient number, since it is larger than the sum of its proper divisors (10339).

2017661 is a wasteful number, since it uses less digits than its factorization.

2017661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10338.

The product of its (nonzero) digits is 504, while the sum is 23.

The square root of 2017661 is about 1420.4439446877. The cubic root of 2017661 is about 126.3618764547.

It can be divided in two parts, 20 and 17661, that multiplied together give a triangular number (353220 = T₈₄₀).

The spelling of 2017661 in words is "two million, seventeen thousand, six hundred sixty-one".