661585084291 has 4 divisors (see below), whose sum is σ = 661587829992. Its totient is φ = 661582338592.

The previous prime is 661585084273. The next prime is 661585084367. The reversal of 661585084291 is 192480585166.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 661585084291 - 2¹¹ = 661585082243 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661585084201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 972505 + ... + 1506298.

It is an arithmetic number, because the mean of its divisors is an integer number (165396957498).

Almost surely, 2^661585084291 is an apocalyptic number.

661585084291 is a deficient number, since it is larger than the sum of its proper divisors (2745701).

661585084291 is a wasteful number, since it uses less digits than its factorization.

661585084291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2745700.

The product of its (nonzero) digits is 4147200, while the sum is 55.

The spelling of 661585084291 in words is "six hundred sixty-one billion, five hundred eighty-five million, eighty-four thousand, two hundred ninety-one".