661696860 has 96 divisors (see below), whose sum is σ = 2086447104. Its totient is φ = 155232000.

The previous prime is 661696853. The next prime is 661696873. The reversal of 661696860 is 68696166.

It is a happy number.

661696860 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 31 ways as a sum of consecutive naturals, for example, 4290 + ... + 36630.

It is an arithmetic number, because the mean of its divisors is an integer number (21733824).

Almost surely, 2^661696860 is an apocalyptic number.

661696860 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661696860, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1043223552).

661696860 is an abundant number, since it is smaller than the sum of its proper divisors (1424750244).

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

661696860 is a wasteful number, since it uses less digits than its factorization.

661696860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32395 (or 32393 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 48.

The square root of 661696860 is about 25723.4690506549. The cubic root of 661696860 is about 871.4042851398.

The spelling of 661696860 in words is "six hundred sixty-one million, six hundred ninety-six thousand, eight hundred sixty".