63645881 has 8 divisors (see below), whose sum is σ = 68680584. Its totient is φ = 58631040.

The previous prime is 63645859. The next prime is 63645917. The reversal of 63645881 is 18854636.

It can be written as a sum of positive squares in 4 ways, for example, as 4494400 + 59151481 = 2120^2 + 7691^2 .

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

It is not a de Polignac number, because 63645881 - 2¹⁴ = 63629497 is a prime.

It is a super-2 number, since 2×63645881² = 8101596336532322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (63644881) 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, 2075 + ... + 11471.

It is an arithmetic number, because the mean of its divisors is an integer number (8585073).

Almost surely, 2^63645881 is an apocalyptic number.

It is an amenable number.

63645881 is a deficient number, since it is larger than the sum of its proper divisors (5034703).

63645881 is a wasteful number, since it uses less digits than its factorization.

63645881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9931.

The product of its digits is 138240, while the sum is 41.

The square root of 63645881 is about 7977.8368622077. The cubic root of 63645881 is about 399.2608872052.

The spelling of 63645881 in words is "sixty-three million, six hundred forty-five thousand, eight hundred eighty-one".