661358808 has 192 divisors, whose sum is σ = 2026252800. Its totient is φ = 193155840.

The previous prime is 661358729. The next prime is 661358851. The reversal of 661358808 is 808853166.

661358808 is a `hidden beast` number, since 6 + 61 + 3 + 588 + 0 + 8 = 666.

661358808 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4057335 + ... + 4057497.

It is an arithmetic number, because the mean of its divisors is an integer number (10553400).

Almost surely, 2^661358808 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 661358808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1013126400).

661358808 is an abundant number, since it is smaller than the sum of its proper divisors (1364893992).

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

661358808 is a wasteful number, since it uses less digits than its factorization.

661358808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342 (or 335 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 45.

The square root of 661358808 is about 25716.8973245219. The cubic root of 661358808 is about 871.2558636299.

The spelling of 661358808 in words is "six hundred sixty-one million, three hundred fifty-eight thousand, eight hundred eight".