1640445437 has 2 divisors, whose sum is σ = 1640445438. Its totient is φ = 1640445436.

The previous prime is 1640445409. The next prime is 1640445451. The reversal of 1640445437 is 7345440461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1017992836 + 622452601 = 31906^2 + 24949^2 .

It is a cyclic number.

It is not a de Polignac number, because 1640445437 - 2¹⁴ = 1640429053 is a prime.

It is a super-2 number, since 2×1640445437² = 5382122463548241938, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1640445437.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1640445467) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 820222718 + 820222719.

It is an arithmetic number, because the mean of its divisors is an integer number (820222719).

Almost surely, 2^1640445437 is an apocalyptic number.

It is an amenable number.

1640445437 is a deficient number, since it is larger than the sum of its proper divisors (1).

1640445437 is an equidigital number, since it uses as much as digits as its factorization.

1640445437 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 161280, while the sum is 38.

The square root of 1640445437 is about 40502.4127306016. The cubic root of 1640445437 is about 1179.3804650250.

Adding to 1640445437 its reverse (7345440461), we get a palindrome (8985885898).

The spelling of 1640445437 in words is "one billion, six hundred forty million, four hundred forty-five thousand, four hundred thirty-seven".