61631818785 has 128 divisors (see below), whose sum is σ = 123047838720. Its totient is φ = 29105049600.

The previous prime is 61631818777. The next prime is 61631818789. The reversal of 61631818785 is 58781813616.

61631818785 is a `hidden beast` number, since 616 + 3 + 1 + 8 + 18 + 7 + 8 + 5 = 666.

It is not a de Polignac number, because 61631818785 - 2³ = 61631818777 is a prime.

It is not an unprimeable number, because it can be changed into a prime (61631818789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 3210315 + ... + 3229455.

It is an arithmetic number, because the mean of its divisors is an integer number (961311240).

Almost surely, 2^61631818785 is an apocalyptic number.

It is an amenable number.

61631818785 is a deficient number, since it is larger than the sum of its proper divisors (61416019935).

61631818785 is a wasteful number, since it uses less digits than its factorization.

61631818785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19256 (or 19250 counting only the distinct ones).

The product of its digits is 1935360, while the sum is 54.

The spelling of 61631818785 in words is "sixty-one billion, six hundred thirty-one million, eight hundred eighteen thousand, seven hundred eighty-five".