661164210 has 192 divisors, whose sum is σ = 2074595328. Its totient is φ = 142826112.

The previous prime is 661164191. The next prime is 661164227. The reversal of 661164210 is 12461166.

661164210 is a `hidden beast` number, since 6 + 6 + 1 + 1 + 642 + 10 = 666.

It is a super-2 number, since 2×661164210² = 874276225169848200, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1492249 + ... + 1492691.

It is an arithmetic number, because the mean of its divisors is an integer number (10805184).

Almost surely, 2^661164210 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661164210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1037297664).

661164210 is an abundant number, since it is smaller than the sum of its proper divisors (1413431118).

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

661164210 is a wasteful number, since it uses less digits than its factorization.

661164210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 589 (or 586 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 661164210 is about 25713.1135804282. The cubic root of 661164210 is about 871.1704025669.

The spelling of 661164210 in words is "six hundred sixty-one million, one hundred sixty-four thousand, two hundred ten".