661715404850 has 24 divisors (see below), whose sum is σ = 1232608722948. Its totient is φ = 264295179200.

The previous prime is 661715404829. The next prime is 661715404897. The reversal of 661715404850 is 58404517166.

It can be written as a sum of positive squares in 6 ways, for example, as 531474534529 + 130240870321 = 729023^2 + 360889^2 .

It is a junction number, because it is equal to n+sod(n) for n = 661715404795 and 661715404804.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 9740381 + ... + 9808080.

Almost surely, 2^661715404850 is an apocalyptic number.

661715404850 is a deficient number, since it is larger than the sum of its proper divisors (570893318098).

661715404850 is a wasteful number, since it uses less digits than its factorization.

661715404850 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19549150 (or 19549145 counting only the distinct ones).

The product of its (nonzero) digits is 806400, while the sum is 47.

The spelling of 661715404850 in words is "six hundred sixty-one billion, seven hundred fifteen million, four hundred four thousand, eight hundred fifty".