63813781 has 2 divisors, whose sum is σ = 63813782. Its totient is φ = 63813780.

The previous prime is 63813731. The next prime is 63813791. The reversal of 63813781 is 18731836.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 58384881 + 5428900 = 7641^2 + 2330^2 .

It is a cyclic number.

It is not a de Polignac number, because 63813781 - 2⁷ = 63813653 is a prime.

It is a super-2 number, since 2×63813781² = 8144397291031922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 63813781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (63813721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 31906890 + 31906891.

It is an arithmetic number, because the mean of its divisors is an integer number (31906891).

Almost surely, 2^63813781 is an apocalyptic number.

63813781 is the 3573-rd centered decagonal number.

It is an amenable number.

63813781 is a deficient number, since it is larger than the sum of its proper divisors (1).

63813781 is an equidigital number, since it uses as much as digits as its factorization.

63813781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24192, while the sum is 37.

The square root of 63813781 is about 7988.3528339702. The cubic root of 63813781 is about 399.6116668654.

The spelling of 63813781 in words is "sixty-three million, eight hundred thirteen thousand, seven hundred eighty-one".