66398691698 has 8 divisors (see below), whose sum is σ = 105456745692. Its totient is φ = 31246443136.

The previous prime is 66398691641. The next prime is 66398691701. The reversal of 66398691698 is 89619689366.

It can be written as a sum of positive squares in 2 ways, for example, as 63270862369 + 3127829329 = 251537^2 + 55927^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 976451315 + ... + 976451382.

Almost surely, 2^66398691698 is an apocalyptic number.

66398691698 is a deficient number, since it is larger than the sum of its proper divisors (39058053994).

66398691698 is a wasteful number, since it uses less digits than its factorization.

66398691698 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1952902716.

The product of its digits is 181398528, while the sum is 71.

The spelling of 66398691698 in words is "sixty-six billion, three hundred ninety-eight million, six hundred ninety-one thousand, six hundred ninety-eight".