661055648 has 48 divisors (see below), whose sum is σ = 1433630016. Its totient is φ = 297546240.

The previous prime is 661055561. The next prime is 661055677. The reversal of 661055648 is 846550166.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27140 + ... + 45372.

It is an arithmetic number, because the mean of its divisors is an integer number (29867292).

Almost surely, 2^661055648 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 661055648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (716815008).

661055648 is an abundant number, since it is smaller than the sum of its proper divisors (772574368).

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

661055648 is a wasteful number, since it uses less digits than its factorization.

661055648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18357 (or 18349 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 41.

The square root of 661055648 is about 25711.0024697599. The cubic root of 661055648 is about 871.1227184078.

The spelling of 661055648 in words is "six hundred sixty-one million, fifty-five thousand, six hundred forty-eight".