63661 has 8 divisors (see below), whose sum is σ = 70560. Its totient is φ = 57072.

The previous prime is 63659. The next prime is 63667. The reversal of 63661 is 16636.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 63661 - 2¹ = 63659 is a prime.

It is a Duffinian number.

63661 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (63667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 726 + ... + 808.

It is an arithmetic number, because the mean of its divisors is an integer number (8820).

2⁶³⁶⁶¹ is an apocalyptic number.

It is an amenable number.

63661 is a deficient number, since it is larger than the sum of its proper divisors (6899).

63661 is a wasteful number, since it uses less digits than its factorization.

63661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155.

The product of its digits is 648, while the sum is 22.

The square root of 63661 is about 252.3113156400. The cubic root of 63661 is about 39.9292499345.

The spelling of 63661 in words is "sixty-three thousand, six hundred sixty-one".