1640520943 has 2 divisors, whose sum is σ = 1640520944. Its totient is φ = 1640520942.

The previous prime is 1640520941. The next prime is 1640520949. The reversal of 1640520943 is 3490250461.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1640520943 - 2¹ = 1640520941 is a prime.

Together with 1640520941, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 1640520899 and 1640520908.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1640520941) 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, 820260471 + 820260472.

It is an arithmetic number, because the mean of its divisors is an integer number (820260472).

Almost surely, 2^1640520943 is an apocalyptic number.

1640520943 is a deficient number, since it is larger than the sum of its proper divisors (1).

1640520943 is an equidigital number, since it uses as much as digits as its factorization.

1640520943 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 34.

The square root of 1640520943 is about 40503.3448371860. The cubic root of 1640520943 is about 1179.3985594874.

The spelling of 1640520943 in words is "one billion, six hundred forty million, five hundred twenty thousand, nine hundred forty-three".