661936705 has 8 divisors (see below), whose sum is σ = 794587752. Its totient is φ = 529373568.

The previous prime is 661936679. The next prime is 661936721. The reversal of 661936705 is 507639166.

It can be written as a sum of positive squares in 4 ways, for example, as 70425664 + 591511041 = 8392^2 + 24321^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 661936705 - 2⁷ = 661936577 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4084 + ... + 36613.

It is an arithmetic number, because the mean of its divisors is an integer number (99323469).

Almost surely, 2^661936705 is an apocalyptic number.

It is an amenable number.

661936705 is a deficient number, since it is larger than the sum of its proper divisors (132651047).

661936705 is a wasteful number, since it uses less digits than its factorization.

661936705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43955.

The product of its (nonzero) digits is 204120, while the sum is 43.

The square root of 661936705 is about 25728.1306161174. The cubic root of 661936705 is about 871.5095582773.

The spelling of 661936705 in words is "six hundred sixty-one million, nine hundred thirty-six thousand, seven hundred five".