661711 has 4 divisors (see below), whose sum is σ = 663400. Its totient is φ = 660024.

The previous prime is 661697. The next prime is 661721. The reversal of 661711 is 117166.

661711 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 661711 - 2⁵ = 661679 is a prime.

It is a super-2 number, since 2×661711² = 875722895042, which contains 22 as substring.

It is a Duffinian number.

661711 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661721) 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, 85 + ... + 1153.

It is an arithmetic number, because the mean of its divisors is an integer number (165850).

2⁶⁶¹⁷¹¹ is an apocalyptic number.

661711 is a deficient number, since it is larger than the sum of its proper divisors (1689).

661711 is a wasteful number, since it uses less digits than its factorization.

661711 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1688.

The product of its digits is 252, while the sum is 22.

The square root of 661711 is about 813.4562065655. The cubic root of 661711 is about 87.1410492196.

Adding to 661711 its reverse (117166), we get a palindrome (778877).

The spelling of 661711 in words is "six hundred sixty-one thousand, seven hundred eleven".