684619639 has 4 divisors (see below), whose sum is σ = 746857800. Its totient is φ = 622381480.

The previous prime is 684619613. The next prime is 684619643. The reversal of 684619639 is 936916486.

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

It is a cyclic number.

It is not a de Polignac number, because 684619639 - 2¹⁵ = 684586871 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (684619669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31119064 + ... + 31119085.

It is an arithmetic number, because the mean of its divisors is an integer number (186714450).

Almost surely, 2^684619639 is an apocalyptic number.

684619639 is a deficient number, since it is larger than the sum of its proper divisors (62238161).

684619639 is a wasteful number, since it uses less digits than its factorization.

684619639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62238160.

The product of its digits is 1679616, while the sum is 52.

The square root of 684619639 is about 26165.2372242256. The cubic root of 684619639 is about 881.3527914971.

The spelling of 684619639 in words is "six hundred eighty-four million, six hundred nineteen thousand, six hundred thirty-nine".