661653784843 has 8 divisors (see below), whose sum is σ = 662941555808. Its totient is φ = 660367266624.

The previous prime is 661653784823. The next prime is 661653784861. The reversal of 661653784843 is 348487356166.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661653784843 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661653784823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 747655 + ... + 1371967.

It is an arithmetic number, because the mean of its divisors is an integer number (82867694476).

Almost surely, 2^661653784843 is an apocalyptic number.

661653784843 is a deficient number, since it is larger than the sum of its proper divisors (1287770965).

661653784843 is a wasteful number, since it uses less digits than its factorization.

661653784843 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 626373.

The product of its digits is 69672960, while the sum is 61.

The spelling of 661653784843 in words is "six hundred sixty-one billion, six hundred fifty-three million, seven hundred eighty-four thousand, eight hundred forty-three".