661541240448 has 768 divisors, whose sum is σ = 2266486185600. Its totient is φ = 190207180800.

The previous prime is 661541240443. The next prime is 661541240471. The reversal of 661541240448 is 844042145166.

661541240448 is a `hidden beast` number, since 6 + 6 + 154 + 12 + 40 + 448 = 666.

It is not an unprimeable number, because it can be changed into a prime (661541240443) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 605252190 + ... + 605253282.

Almost surely, 2^661541240448 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661541240448, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1133243092800).

661541240448 is an abundant number, since it is smaller than the sum of its proper divisors (1604944945152).

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

661541240448 is a wasteful number, since it uses less digits than its factorization.

661541240448 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1223 (or 1199 counting only the distinct ones).

The product of its (nonzero) digits is 737280, while the sum is 45.

The spelling of 661541240448 in words is "six hundred sixty-one billion, five hundred forty-one million, two hundred forty thousand, four hundred forty-eight".