611681 has 4 divisors (see below), whose sum is σ = 699072. Its totient is φ = 524292.

The previous prime is 611671. The next prime is 611693. The reversal of 611681 is 186116.

It is a happy number.

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 a de Polignac number, because none of the positive numbers 2^k-611681 is a prime.

It is a super-2 number, since 2×611681² = 748307291522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (611621) 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, 43685 + ... + 43698.

It is an arithmetic number, because the mean of its divisors is an integer number (174768).

2⁶¹¹⁶⁸¹ is an apocalyptic number.

It is an amenable number.

611681 is a deficient number, since it is larger than the sum of its proper divisors (87391).

611681 is an equidigital number, since it uses as much as digits as its factorization.

611681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87390.

The product of its digits is 288, while the sum is 23.

The square root of 611681 is about 782.1003771895. The cubic root of 611681 is about 84.8870934592.

Adding to 611681 its reverse (186116), we get a palindrome (797797).

The spelling of 611681 in words is "six hundred eleven thousand, six hundred eighty-one".