661191488 has 112 divisors (see below), whose sum is σ = 1474744320. Its totient is φ = 292621824.

The previous prime is 661191451. The next prime is 661191533. The reversal of 661191488 is 884191166.

661191488 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1314245 + ... + 1314747.

It is an arithmetic number, because the mean of its divisors is an integer number (13167360).

Almost surely, 2^661191488 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 661191488, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (737372160).

661191488 is an abundant number, since it is smaller than the sum of its proper divisors (813552832).

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

661191488 is a wasteful number, since it uses less digits than its factorization.

661191488 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 604 (or 594 counting only the distinct ones).

The product of its digits is 82944, while the sum is 44.

The square root of 661191488 is about 25713.6440046914. The cubic root of 661191488 is about 871.1823831808.

The spelling of 661191488 in words is "six hundred sixty-one million, one hundred ninety-one thousand, four hundred eighty-eight".