661041217 has 4 divisors (see below), whose sum is σ = 695832880. Its totient is φ = 626249556.

The previous prime is 661041197. The next prime is 661041221. The reversal of 661041217 is 712140166.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 661041217 - 2¹⁵ = 661008449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661041287) 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 3 ways as a sum of consecutive naturals, for example, 17395803 + ... + 17395840.

It is an arithmetic number, because the mean of its divisors is an integer number (173958220).

Almost surely, 2^661041217 is an apocalyptic number.

It is an amenable number.

661041217 is a deficient number, since it is larger than the sum of its proper divisors (34791663).

661041217 is a wasteful number, since it uses less digits than its factorization.

661041217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34791662.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 661041217 is about 25710.7218296181. The cubic root of 661041217 is about 871.1163794239.

The spelling of 661041217 in words is "six hundred sixty-one million, forty-one thousand, two hundred seventeen".