1640243069 has 2 divisors, whose sum is σ = 1640243070. Its totient is φ = 1640243068.

The previous prime is 1640243063. The next prime is 1640243123. The reversal of 1640243069 is 9603420461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1131515044 + 508728025 = 33638^2 + 22555^2 .

It is a cyclic number.

It is not a de Polignac number, because 1640243069 - 2¹⁶ = 1640177533 is a prime.

It is a super-2 number, since 2×1640243069² = 5380794650805077522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1640243063) 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 as a sum of consecutive naturals, namely, 820121534 + 820121535.

It is an arithmetic number, because the mean of its divisors is an integer number (820121535).

Almost surely, 2^1640243069 is an apocalyptic number.

It is an amenable number.

1640243069 is a deficient number, since it is larger than the sum of its proper divisors (1).

1640243069 is an equidigital number, since it uses as much as digits as its factorization.

1640243069 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 31104, while the sum is 35.

The square root of 1640243069 is about 40499.9144320084. The cubic root of 1640243069 is about 1179.3319662706.

The spelling of 1640243069 in words is "one billion, six hundred forty million, two hundred forty-three thousand, sixty-nine".