63728809 has 2 divisors, whose sum is σ = 63728810. Its totient is φ = 63728808.

The previous prime is 63728789. The next prime is 63728827. The reversal of 63728809 is 90882736.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42614784 + 21114025 = 6528^2 + 4595^2 .

It is a cyclic number.

It is not a de Polignac number, because 63728809 - 2⁹ = 63728297 is a prime.

It is a super-2 number, since 2×63728809² = 8122722193116962, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (63728849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 31864404 + 31864405.

It is an arithmetic number, because the mean of its divisors is an integer number (31864405).

Almost surely, 2^63728809 is an apocalyptic number.

It is an amenable number.

63728809 is a deficient number, since it is larger than the sum of its proper divisors (1).

63728809 is an equidigital number, since it uses as much as digits as its factorization.

63728809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 145152, while the sum is 43.

The square root of 63728809 is about 7983.0325691431. The cubic root of 63728809 is about 399.4342188566.

The spelling of 63728809 in words is "sixty-three million, seven hundred twenty-eight thousand, eight hundred nine".