640559769 has 8 divisors (see below), whose sum is σ = 874911072. Its totient is φ = 416624160.

The previous prime is 640559767. The next prime is 640559783. The reversal of 640559769 is 967955046.

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

It is not a de Polignac number, because 640559769 - 2¹ = 640559767 is a prime.

It is a super-2 number, since 2×640559769² = 820633635322666722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (640559761) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2603779 + ... + 2604024.

It is an arithmetic number, because the mean of its divisors is an integer number (109363884).

Almost surely, 2^640559769 is an apocalyptic number.

It is an amenable number.

640559769 is a deficient number, since it is larger than the sum of its proper divisors (234351303).

640559769 is a wasteful number, since it uses less digits than its factorization.

640559769 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5207847.

The product of its (nonzero) digits is 2041200, while the sum is 51.

The square root of 640559769 is about 25309.2822695548. The cubic root of 640559769 is about 862.0250498298.

The spelling of 640559769 in words is "six hundred forty million, five hundred fifty-nine thousand, seven hundred sixty-nine".