63681813 has 48 divisors (see below), whose sum is σ = 106260336. Its totient is φ = 36403200.

The previous prime is 63681811. The next prime is 63681823. The reversal of 63681813 is 31818636.

63681813 is a `hidden beast` number, since 636 + 8 + 1 + 8 + 13 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 49284 + 63632529 = 222^2 + 7977^2 .

It is not a de Polignac number, because 63681813 - 2¹ = 63681811 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (63681811) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 200731 + ... + 201047.

It is an arithmetic number, because the mean of its divisors is an integer number (2213757).

Almost surely, 2^63681813 is an apocalyptic number.

It is an amenable number.

63681813 is a deficient number, since it is larger than the sum of its proper divisors (42578523).

63681813 is a wasteful number, since it uses less digits than its factorization.

63681813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 454 (or 451 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 63681813 is about 7980.0885333435. The cubic root of 63681813 is about 399.3360088158.

The spelling of 63681813 in words is "sixty-three million, six hundred eighty-one thousand, eight hundred thirteen".