661551755700 has 72 divisors (see below), whose sum is σ = 2088097915680. Its totient is φ = 160376182400.

The previous prime is 661551755663. The next prime is 661551755707. The reversal of 661551755700 is 7557155166.

It is a self number, because there is not a number n which added to its sum of digits gives 661551755700.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661551755707) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 100231815 + ... + 100238414.

It is an arithmetic number, because the mean of its divisors is an integer number (29001359940).

Almost surely, 2^661551755700 is an apocalyptic number.

661551755700 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

661551755700 is an abundant number, since it is smaller than the sum of its proper divisors (1426546159980).

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

661551755700 is a wasteful number, since it uses less digits than its factorization.

661551755700 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200470257 (or 200470250 counting only the distinct ones).

The product of its (nonzero) digits is 1102500, while the sum is 48.

The spelling of 661551755700 in words is "six hundred sixty-one billion, five hundred fifty-one million, seven hundred fifty-five thousand, seven hundred".