656128491 has 8 divisors (see below), whose sum is σ = 875644224. Its totient is φ = 437015880.

The previous prime is 656128489. The next prime is 656128519. The reversal of 656128491 is 194821656.

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

It is not a de Polignac number, because 656128491 - 2¹ = 656128489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (656126491) 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 7 ways as a sum of consecutive naturals, for example, 96961 + ... + 103506.

It is an arithmetic number, because the mean of its divisors is an integer number (109455528).

Almost surely, 2^656128491 is an apocalyptic number.

656128491 is a deficient number, since it is larger than the sum of its proper divisors (219515733).

656128491 is a wasteful number, since it uses less digits than its factorization.

656128491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 201561.

The product of its digits is 103680, while the sum is 42.

The square root of 656128491 is about 25615.0051922696. The cubic root of 656128491 is about 868.9530238131.

The spelling of 656128491 in words is "six hundred fifty-six million, one hundred twenty-eight thousand, four hundred ninety-one".