660784401 has 12 divisors (see below), whose sum is σ = 987379380. Its totient is φ = 425332320.

The previous prime is 660784387. The next prime is 660784403. The reversal of 660784401 is 104487066.

660784401 is a `hidden beast` number, since 6 + 607 + 8 + 4 + 40 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 406062801 + 254721600 = 20151^2 + 15960^2 .

It is not a de Polignac number, because 660784401 - 2⁹ = 660783889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (660784403) 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 11 ways as a sum of consecutive naturals, for example, 1265610 + ... + 1266131.

It is an arithmetic number, because the mean of its divisors is an integer number (82281615).

Almost surely, 2^660784401 is an apocalyptic number.

It is an amenable number.

660784401 is a deficient number, since it is larger than the sum of its proper divisors (326594979).

660784401 is a wasteful number, since it uses less digits than its factorization.

660784401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2531776 (or 2531773 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The square root of 660784401 is about 25705.7270078090. The cubic root of 660784401 is about 871.0035545873.

The spelling of 660784401 in words is "six hundred sixty million, seven hundred eighty-four thousand, four hundred one".