63661861 has 8 divisors (see below), whose sum is σ = 66911040. Its totient is φ = 60452832.

The previous prime is 63661853. The next prime is 63661901. The reversal of 63661861 is 16816636.

It is a happy number.

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

It is not a de Polignac number, because 63661861 - 2³ = 63661853 is a prime.

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 63661861.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (63661811) 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, 6760 + ... + 13153.

It is an arithmetic number, because the mean of its divisors is an integer number (8363880).

Almost surely, 2^63661861 is an apocalyptic number.

It is an amenable number.

63661861 is a deficient number, since it is larger than the sum of its proper divisors (3249179).

63661861 is a wasteful number, since it uses less digits than its factorization.

63661861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20075.

The product of its digits is 31104, while the sum is 37.

The square root of 63661861 is about 7978.8383239667. The cubic root of 63661861 is about 399.2942994490.

The spelling of 63661861 in words is "sixty-three million, six hundred sixty-one thousand, eight hundred sixty-one".