661748161 has 8 divisors (see below), whose sum is σ = 671686400. Its totient is φ = 651849120.

The previous prime is 661748149. The next prime is 661748177. The reversal of 661748161 is 161847166.

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 661748161 - 2¹⁹ = 661223873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661748261) 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, 25141 + ... + 44221.

It is an arithmetic number, because the mean of its divisors is an integer number (83960800).

Almost surely, 2^661748161 is an apocalyptic number.

It is an amenable number.

661748161 is a deficient number, since it is larger than the sum of its proper divisors (9938239).

661748161 is a wasteful number, since it uses less digits than its factorization.

661748161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19599.

The product of its digits is 48384, while the sum is 40.

The square root of 661748161 is about 25724.4661946560. The cubic root of 661748161 is about 871.4268043923.

The spelling of 661748161 in words is "six hundred sixty-one million, seven hundred forty-eight thousand, one hundred sixty-one".