640575469 has 4 divisors (see below), whose sum is σ = 641040700. Its totient is φ = 640110240.

The previous prime is 640575401. The next prime is 640575473. The reversal of 640575469 is 964575046.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 206353225 + 434222244 = 14365^2 + 20838^2 .

It is a cyclic number.

It is not a de Polignac number, because 640575469 - 2¹⁷ = 640444397 is a prime.

It is a super-2 number, since 2×640575469² = 820673862969139922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640575499) 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, 230544 + ... + 233305.

It is an arithmetic number, because the mean of its divisors is an integer number (160260175).

Almost surely, 2^640575469 is an apocalyptic number.

640575469 is the 14613-rd hex number.

It is an amenable number.

640575469 is a deficient number, since it is larger than the sum of its proper divisors (465231).

640575469 is a wasteful number, since it uses less digits than its factorization.

640575469 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 465230.

The product of its (nonzero) digits is 907200, while the sum is 46.

The square root of 640575469 is about 25309.5924305391. The cubic root of 640575469 is about 862.0320924632.

The spelling of 640575469 in words is "six hundred forty million, five hundred seventy-five thousand, four hundred sixty-nine".