63816381 has 24 divisors (see below), whose sum is σ = 94256760. Its totient is φ = 41596416.

The previous prime is 63816367. The next prime is 63816391. The reversal of 63816381 is 18361836.

63816381 is a `hidden beast` number, since 638 + 16 + 3 + 8 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 4372281 + 59444100 = 2091^2 + 7710^2 .

It is not a de Polignac number, because 63816381 - 2⁵ = 63816349 is a prime.

It is a super-2 number, since 2×63816381² = 8145060967874322, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (63816301) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 89655 + ... + 90363.

It is an arithmetic number, because the mean of its divisors is an integer number (3927365).

Almost surely, 2^63816381 is an apocalyptic number.

It is an amenable number.

63816381 is a deficient number, since it is larger than the sum of its proper divisors (30440379).

63816381 is a wasteful number, since it uses less digits than its factorization.

63816381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 925 (or 922 counting only the distinct ones).

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

The square root of 63816381 is about 7988.5155692406. The cubic root of 63816381 is about 399.6170939911.

The spelling of 63816381 in words is "sixty-three million, eight hundred sixteen thousand, three hundred eighty-one".