61278581385 has 24 divisors (see below), whose sum is σ = 121389952320. Its totient is φ = 28013065632.

The previous prime is 61278581383. The next prime is 61278581389. The reversal of 61278581385 is 58318587216.

61278581385 is a `hidden beast` number, since 6 + 1 + 27 + 8 + 581 + 38 + 5 = 666.

61278581385 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 61278581385 - 2¹ = 61278581383 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (61278581383) 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, 97267275 + ... + 97267904.

It is an arithmetic number, because the mean of its divisors is an integer number (5057914680).

Almost surely, 2^61278581385 is an apocalyptic number.

It is an amenable number.

61278581385 is a deficient number, since it is larger than the sum of its proper divisors (60111370935).

61278581385 is a wasteful number, since it uses less digits than its factorization.

61278581385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194535197 (or 194535194 counting only the distinct ones).

The product of its digits is 3225600, while the sum is 54.

The spelling of 61278581385 in words is "sixty-one billion, two hundred seventy-eight million, five hundred eighty-one thousand, three hundred eighty-five".