66840415 has 16 divisors (see below), whose sum is σ = 83980800. Its totient is φ = 50973472.

The previous prime is 66840409. The next prime is 66840419. The reversal of 66840415 is 51404866.

It is a cyclic number.

It is not a de Polignac number, because 66840415 - 2³ = 66840407 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66840419) 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, 40476 + ... + 42094.

It is an arithmetic number, because the mean of its divisors is an integer number (5248800).

Almost surely, 2^66840415 is an apocalyptic number.

66840415 is a deficient number, since it is larger than the sum of its proper divisors (17140385).

66840415 is a wasteful number, since it uses less digits than its factorization.

66840415 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2006.

The product of its (nonzero) digits is 23040, while the sum is 34.

The square root of 66840415 is about 8175.5987548314. The cubic root of 66840415 is about 405.8320849464.

The spelling of 66840415 in words is "sixty-six million, eight hundred forty thousand, four hundred fifteen".