63855661 has 2 divisors, whose sum is σ = 63855662. Its totient is φ = 63855660.

The previous prime is 63855647. The next prime is 63855679. The reversal of 63855661 is 16655836.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 59382436 + 4473225 = 7706^2 + 2115^2 .

It is a cyclic number.

It is not a de Polignac number, because 63855661 - 2⁹ = 63855149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (63855161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 31927830 + 31927831.

It is an arithmetic number, because the mean of its divisors is an integer number (31927831).

Almost surely, 2^63855661 is an apocalyptic number.

It is an amenable number.

63855661 is a deficient number, since it is larger than the sum of its proper divisors (1).

63855661 is an equidigital number, since it uses as much as digits as its factorization.

63855661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 129600, while the sum is 40.

The square root of 63855661 is about 7990.9737203923. The cubic root of 63855661 is about 399.6990674057.

It can be divided in two parts, 63855 and 661, that added together give a square (64516 = 254²).

The spelling of 63855661 in words is "sixty-three million, eight hundred fifty-five thousand, six hundred sixty-one".