1640243091 has 16 divisors (see below), whose sum is σ = 2319494400. Its totient is φ = 1028802720.

The previous prime is 1640243069. The next prime is 1640243123. The reversal of 1640243091 is 1903420461.

It is not a de Polignac number, because 1640243091 - 2¹³ = 1640234899 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1640243021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 190641 + ... + 199058.

It is an arithmetic number, because the mean of its divisors is an integer number (144968400).

Almost surely, 2^1640243091 is an apocalyptic number.

1640243091 is a deficient number, since it is larger than the sum of its proper divisors (679251309).

1640243091 is a wasteful number, since it uses less digits than its factorization.

1640243091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 389786.

The product of its (nonzero) digits is 5184, while the sum is 30.

The square root of 1640243091 is about 40499.9147036139. The cubic root of 1640243091 is about 1179.3319715433.

The spelling of 1640243091 in words is "one billion, six hundred forty million, two hundred forty-three thousand, ninety-one".