61685012778 has 32 divisors (see below), whose sum is σ = 124174028160. Its totient is φ = 20427800640.

The previous prime is 61685012747. The next prime is 61685012791. The reversal of 61685012778 is 87721058616.

It is a happy number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 61685012778.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2017888 + ... + 2048228.

It is an arithmetic number, because the mean of its divisors is an integer number (3880438380).

Almost surely, 2^61685012778 is an apocalyptic number.

61685012778 is an abundant number, since it is smaller than the sum of its proper divisors (62489015382).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

61685012778 is a wasteful number, since it uses less digits than its factorization.

61685012778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32542.

The product of its (nonzero) digits is 1128960, while the sum is 51.

The spelling of 61685012778 in words is "sixty-one billion, six hundred eighty-five million, twelve thousand, seven hundred seventy-eight".