639244400569 has 4 divisors (see below), whose sum is σ = 640363918480. Its totient is φ = 638124882660.

The previous prime is 639244400513. The next prime is 639244400573. The reversal of 639244400569 is 965004442936.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 639244400569 - 2¹¹ = 639244398521 is a prime.

It is a super-2 number, since 2×639244400569² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639244400269) 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, 559758099 + ... + 559759240.

It is an arithmetic number, because the mean of its divisors is an integer number (160090979620).

Almost surely, 2^639244400569 is an apocalyptic number.

It is an amenable number.

639244400569 is a deficient number, since it is larger than the sum of its proper divisors (1119517911).

639244400569 is a wasteful number, since it uses less digits than its factorization.

639244400569 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1119517910.

The product of its (nonzero) digits is 5598720, while the sum is 52.

The spelling of 639244400569 in words is "six hundred thirty-nine billion, two hundred forty-four million, four hundred thousand, five hundred sixty-nine".