661614679609 has 15 divisors (see below), whose sum is σ = 716896255803. Its totient is φ = 610594352784.

The previous prime is 661614679577. The next prime is 661614679637. The reversal of 661614679609 is 906976416166.

It is a happy number.

The square root of 661614679609 is 813397.

It is a perfect power (a square), and thus also a powerful number.

661614679609 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 7 ways, for example, as 616342755625 + 45271923984 = 785075^2 + 212772^2 .

It is not a de Polignac number, because 661614679609 - 2⁵ = 661614679577 is a prime.

It is not an unprimeable number, because it can be changed into a prime (661614679669) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 137461687 + ... + 137466499.

Almost surely, 2^661614679609 is an apocalyptic number.

661614679609 is the 813397-th square number.

661614679609 is the 406699-th centered octagonal number.

It is an amenable number.

661614679609 is a deficient number, since it is larger than the sum of its proper divisors (55281576194).

661614679609 is an frugal number, since it uses more digits than its factorization.

661614679609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9678 (or 4826 counting only the distinct ones).

The product of its (nonzero) digits is 17635968, while the sum is 61.

The spelling of 661614679609 in words is "six hundred sixty-one billion, six hundred fourteen million, six hundred seventy-nine thousand, six hundred nine".