661653633546 has 12 divisors (see below), whose sum is σ = 1433582872722. Its totient is φ = 220551211176.

The previous prime is 661653633539. The next prime is 661653633611. The reversal of 661653633546 is 645336356166.

661653633546 is a `hidden beast` number, since 6 + 6 + 1 + 65 + 3 + 6 + 33 + 546 = 666.

It can be written as a sum of positive squares in only one way, i.e., 382061208321 + 279592425225 = 618111^2 + 528765^2 .

It is a super-3 number, since 3×661653633546³ (a number of 36 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 661653633492 and 661653633501.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 18379267581 + ... + 18379267616.

Almost surely, 2^661653633546 is an apocalyptic number.

661653633546 is an abundant number, since it is smaller than the sum of its proper divisors (771929239176).

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

661653633546 is a wasteful number, since it uses less digits than its factorization.

661653633546 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36758535205 (or 36758535202 counting only the distinct ones).

The product of its digits is 20995200, while the sum is 54.

The spelling of 661653633546 in words is "six hundred sixty-one billion, six hundred fifty-three million, six hundred thirty-three thousand, five hundred forty-six".