661209670 has 16 divisors (see below), whose sum is σ = 1298375568. Its totient is φ = 240439840.

The previous prime is 661209649. The next prime is 661209673. The reversal of 661209670 is 76902166.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661209673) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3005389 + ... + 3005608.

It is an arithmetic number, because the mean of its divisors is an integer number (81148473).

Almost surely, 2^661209670 is an apocalyptic number.

661209670 is a deficient number, since it is larger than the sum of its proper divisors (637165898).

661209670 is a wasteful number, since it uses less digits than its factorization.

661209670 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6011015.

The product of its (nonzero) digits is 27216, while the sum is 37.

The square root of 661209670 is about 25713.9975499727. The cubic root of 661209670 is about 871.1903686098.

It can be divided in two parts, 6612096 and 70, that added together give a palindrome (6612166).

The spelling of 661209670 in words is "six hundred sixty-one million, two hundred nine thousand, six hundred seventy".