1640464565 has 8 divisors (see below), whose sum is σ = 1968936120. Its totient is φ = 1312119232.

The previous prime is 1640464559. The next prime is 1640464601. The reversal of 1640464565 is 5654640461.

It can be written as a sum of positive squares in 4 ways, for example, as 339996721 + 1300467844 = 18439^2 + 36062^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1640464565 - 2²² = 1636270261 is a prime.

It is a super-2 number, since 2×1640464565² = 5382247978041278450, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 110 + ... + 57279.

It is an arithmetic number, because the mean of its divisors is an integer number (246117015).

Almost surely, 2^1640464565 is an apocalyptic number.

It is an amenable number.

1640464565 is a deficient number, since it is larger than the sum of its proper divisors (328471555).

1640464565 is an equidigital number, since it uses as much as digits as its factorization.

1640464565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63111.

The product of its (nonzero) digits is 345600, while the sum is 41.

The square root of 1640464565 is about 40502.6488639941. The cubic root of 1640464565 is about 1179.3850489632.

The spelling of 1640464565 in words is "one billion, six hundred forty million, four hundred sixty-four thousand, five hundred sixty-five".