661111530 has 64 divisors (see below), whose sum is σ = 1617739776. Its totient is φ = 172872000.

The previous prime is 661111519. The next prime is 661111553. The reversal of 661111530 is 35111166.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 661111530.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 448695 + ... + 450165.

It is an arithmetic number, because the mean of its divisors is an integer number (25277184).

Almost surely, 2^661111530 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661111530, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (808869888).

661111530 is an abundant number, since it is smaller than the sum of its proper divisors (956628246).

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

661111530 is a wasteful number, since it uses less digits than its factorization.

661111530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1763.

The product of its (nonzero) digits is 540, while the sum is 24.

The square root of 661111530 is about 25712.0891799947. The cubic root of 661111530 is about 871.1472643535.

Adding to 661111530 its reverse (35111166), we get a palindrome (696222696).

The spelling of 661111530 in words is "six hundred sixty-one million, one hundred eleven thousand, five hundred thirty".