639780090069 has 4 divisors (see below), whose sum is σ = 853040120096. Its totient is φ = 426520060044.

The previous prime is 639780090067. The next prime is 639780090149. The reversal of 639780090069 is 960090087936.

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 not a de Polignac number, because 639780090069 - 2¹ = 639780090067 is a prime.

It is a super-2 number, since 2×639780090069² (a number of 24 digits) 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 (639780090067) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 106630015009 + ... + 106630015014.

It is an arithmetic number, because the mean of its divisors is an integer number (213260030024).

Almost surely, 2^639780090069 is an apocalyptic number.

It is an amenable number.

639780090069 is a deficient number, since it is larger than the sum of its proper divisors (213260030027).

639780090069 is a wasteful number, since it uses less digits than its factorization.

639780090069 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213260030026.

The product of its (nonzero) digits is 4408992, while the sum is 57.

The spelling of 639780090069 in words is "six hundred thirty-nine billion, seven hundred eighty million, ninety thousand, sixty-nine".