661361299800 has 96 divisors (see below), whose sum is σ = 2050433049600. Its totient is φ = 176344689280.

The previous prime is 661361299777. The next prime is 661361299811. The reversal of 661361299800 is 8992163166.

It is a congruent number.

It is an unprimeable number.

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, 6312241 + ... + 6416159.

It is an arithmetic number, because the mean of its divisors is an integer number (21358677600).

Almost surely, 2^661361299800 is an apocalyptic number.

661361299800 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

661361299800 is an abundant number, since it is smaller than the sum of its proper divisors (1389071749800).

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

661361299800 is a wasteful number, since it uses less digits than its factorization.

661361299800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114545 (or 114536 counting only the distinct ones).

The product of its (nonzero) digits is 839808, while the sum is 51.

The spelling of 661361299800 in words is "six hundred sixty-one billion, three hundred sixty-one million, two hundred ninety-nine thousand, eight hundred".