63661278385 has 16 divisors (see below), whose sum is σ = 77203547856. Its totient is φ = 50390581248.

The previous prime is 63661278361. The next prime is 63661278389. The reversal of 63661278385 is 58387216636.

It can be written as a sum of positive squares in 8 ways, for example, as 691900416 + 62969377969 = 26304^2 + 250937^2 .

It is a cyclic number.

It is not a de Polignac number, because 63661278385 - 2⁵ = 63661278353 is a prime.

It is a super-2 number, since 2×63661278385² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (63661278389) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 228367 + ... + 423643.

It is an arithmetic number, because the mean of its divisors is an integer number (4825221741).

Almost surely, 2^63661278385 is an apocalyptic number.

It is an amenable number.

63661278385 is a deficient number, since it is larger than the sum of its proper divisors (13542269471).

63661278385 is a wasteful number, since it uses less digits than its factorization.

63661278385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195972.

The product of its digits is 8709120, while the sum is 55.

The spelling of 63661278385 in words is "sixty-three billion, six hundred sixty-one million, two hundred seventy-eight thousand, three hundred eighty-five".