1640136618 has 12 divisors (see below), whose sum is σ = 3553629378. Its totient is φ = 546712200.

The previous prime is 1640136613. The next prime is 1640136649. The reversal of 1640136618 is 8166310461.

1640136618 is a `hidden beast` number, since 1 + 6 + 4 + 0 + 1 + 36 + 618 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1003432329 + 636704289 = 31677^2 + 25233^2 .

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1640136613) 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 5 ways as a sum of consecutive naturals, for example, 45559333 + ... + 45559368.

Almost surely, 2^1640136618 is an apocalyptic number.

1640136618 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1640136618 is an abundant number, since it is smaller than the sum of its proper divisors (1913492760).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1640136618 is a wasteful number, since it uses less digits than its factorization.

1640136618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91118709 (or 91118706 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 1640136618 is about 40498.6001980315. The cubic root of 1640136618 is about 1179.3064530229.

The spelling of 1640136618 in words is "one billion, six hundred forty million, one hundred thirty-six thousand, six hundred eighteen".