661988206 has 16 divisors (see below), whose sum is σ = 1083720960. Its totient is φ = 300773880.

The previous prime is 661988203. The next prime is 661988219. The reversal of 661988206 is 602889166.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661988203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 61435 + ... + 71401.

It is an arithmetic number, because the mean of its divisors is an integer number (67732560).

Almost surely, 2^661988206 is an apocalyptic number.

661988206 is a deficient number, since it is larger than the sum of its proper divisors (421732754).

661988206 is a wasteful number, since it uses less digits than its factorization.

661988206 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12999.

The product of its (nonzero) digits is 248832, while the sum is 46.

The square root of 661988206 is about 25729.1314661028. The cubic root of 661988206 is about 871.5321598591.

The spelling of 661988206 in words is "six hundred sixty-one million, nine hundred eighty-eight thousand, two hundred six".