64661 has 2 divisors, whose sum is σ = 64662. Its totient is φ = 64660.

The previous prime is 64633. The next prime is 64663. The reversal of 64661 is 16646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 36100 + 28561 = 190^2 + 169^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64661 is a prime.

Together with 64663, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 13.

It is a nialpdrome in base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32330 + 32331.

It is an arithmetic number, because the mean of its divisors is an integer number (32331).

2⁶⁴⁶⁶¹ is an apocalyptic number.

It is an amenable number.

64661 is a deficient number, since it is larger than the sum of its proper divisors (1).

64661 is an equidigital number, since it uses as much as digits as its factorization.

64661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 864, while the sum is 23.

The square root of 64661 is about 254.2852728728. The cubic root of 64661 is about 40.1372369454.

It can be divided in two parts, 646 and 61, that added together give a palindrome (707).

The spelling of 64661 in words is "sixty-four thousand, six hundred sixty-one".