66809404390 has 16 divisors (see below), whose sum is σ = 120296040480. Its totient is φ = 26715070080.

The previous prime is 66809404367. The next prime is 66809404411. The reversal of 66809404390 is 9340490866.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1054131 + ... + 1115710.

It is an arithmetic number, because the mean of its divisors is an integer number (7518502530).

Almost surely, 2^66809404390 is an apocalyptic number.

66809404390 is a deficient number, since it is larger than the sum of its proper divisors (53486636090).

66809404390 is a wasteful number, since it uses less digits than its factorization.

66809404390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2172927.

The product of its (nonzero) digits is 1119744, while the sum is 49.

The spelling of 66809404390 in words is "sixty-six billion, eight hundred nine million, four hundred four thousand, three hundred ninety".