661984855701 has 8 divisors (see below), whose sum is σ = 950542356960. Its totient is φ = 407375295792.

The previous prime is 661984855687. The next prime is 661984855703. The reversal of 661984855701 is 107558489166.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 661984855701 - 2⁵ = 661984855669 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661984855703) 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 7 ways as a sum of consecutive naturals, for example, 8486985291 + ... + 8486985368.

It is an arithmetic number, because the mean of its divisors is an integer number (118817794620).

Almost surely, 2^661984855701 is an apocalyptic number.

It is an amenable number.

661984855701 is a deficient number, since it is larger than the sum of its proper divisors (288557501259).

661984855701 is a wasteful number, since it uses less digits than its factorization.

661984855701 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16973970675.

The product of its (nonzero) digits is 14515200, while the sum is 60.

The spelling of 661984855701 in words is "six hundred sixty-one billion, nine hundred eighty-four million, eight hundred fifty-five thousand, seven hundred one".