571661 has 4 divisors (see below), whose sum is σ = 583872. Its totient is φ = 559452.

The previous prime is 571657. The next prime is 571673. The reversal of 571661 is 166175.

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 571661 - 2² = 571657 is a prime.

It is a super-3 number, since 3×571661³ = 560450097112433343, which contains 333 as substring.

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 571661.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 571661.

It is not an unprimeable number, because it can be changed into a prime (571601) 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, 6035 + ... + 6128.

It is an arithmetic number, because the mean of its divisors is an integer number (145968).

2⁵⁷¹⁶⁶¹ is an apocalyptic number.

It is an amenable number.

571661 is a deficient number, since it is larger than the sum of its proper divisors (12211).

571661 is a wasteful number, since it uses less digits than its factorization.

571661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12210.

The product of its digits is 1260, while the sum is 26.

The square root of 571661 is about 756.0826674379. The cubic root of 571661 is about 82.9939028763.

The spelling of 571661 in words is "five hundred seventy-one thousand, six hundred sixty-one".