1640445577 has 4 divisors (see below), whose sum is σ = 1643989120. Its totient is φ = 1636902036.

The previous prime is 1640445551. The next prime is 1640445619. The reversal of 1640445577 is 7755440461.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 7755440461 = 8681 ⋅893381.

It is a cyclic number.

It is not a de Polignac number, because 1640445577 - 2¹¹ = 1640443529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1640445517) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1771077 + ... + 1772002.

It is an arithmetic number, because the mean of its divisors is an integer number (410997280).

Almost surely, 2^1640445577 is an apocalyptic number.

It is an amenable number.

1640445577 is a deficient number, since it is larger than the sum of its proper divisors (3543543).

1640445577 is an equidigital number, since it uses as much as digits as its factorization.

1640445577 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3543542.

The product of its (nonzero) digits is 470400, while the sum is 43.

The square root of 1640445577 is about 40502.4144588937. The cubic root of 1640445577 is about 1179.3804985755.

The spelling of 1640445577 in words is "one billion, six hundred forty million, four hundred forty-five thousand, five hundred seventy-seven".