66986409 has 16 divisors (see below), whose sum is σ = 108079488. Its totient is φ = 36026112.

The previous prime is 66986407. The next prime is 66986411. The reversal of 66986409 is 90468966.

It is an interprime number because it is at equal distance from previous prime (66986407) and next prime (66986411).

It is not a de Polignac number, because 66986409 - 2¹ = 66986407 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66986407) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 93462 + ... + 94175.

It is an arithmetic number, because the mean of its divisors is an integer number (6754968).

Almost surely, 2^66986409 is an apocalyptic number.

It is an amenable number.

66986409 is a deficient number, since it is larger than the sum of its proper divisors (41093079).

66986409 is a wasteful number, since it uses less digits than its factorization.

66986409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 187664.

The product of its (nonzero) digits is 559872, while the sum is 48.

The square root of 66986409 is about 8184.5225273073. The cubic root of 66986409 is about 406.1273452520.

It can be divided in two parts, 669 and 86409, that added together give a palindrome (87078).

The spelling of 66986409 in words is "sixty-six million, nine hundred eighty-six thousand, four hundred nine".