661066806 has 16 divisors (see below), whose sum is σ = 1327163904. Its totient is φ = 219517224.

The previous prime is 661066801. The next prime is 661066807. The reversal of 661066806 is 608660166.

661066806 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661066801) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 207886 + ... + 211041.

It is an arithmetic number, because the mean of its divisors is an integer number (82947744).

Almost surely, 2^661066806 is an apocalyptic number.

661066806 is an abundant number, since it is smaller than the sum of its proper divisors (666097098).

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

661066806 is a wasteful number, since it uses less digits than its factorization.

661066806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 419195.

The product of its (nonzero) digits is 62208, while the sum is 39.

The square root of 661066806 is about 25711.2194576609. The cubic root of 661066806 is about 871.1276196254.

The spelling of 661066806 in words is "six hundred sixty-one million, sixty-six thousand, eight hundred six".