66613855 has 16 divisors (see below), whose sum is σ = 99661824. Its totient is φ = 41525280.

The previous prime is 66613853. The next prime is 66613861. The reversal of 66613855 is 55831666.

It is not a de Polignac number, because 66613855 - 2¹ = 66613853 is a prime.

It is a super-2 number, since 2×66613855² = 8874811355922050, which 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 (66613853) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 86127 + ... + 86896.

It is an arithmetic number, because the mean of its divisors is an integer number (6228864).

Almost surely, 2^66613855 is an apocalyptic number.

66613855 is a deficient number, since it is larger than the sum of its proper divisors (33047969).

66613855 is a wasteful number, since it uses less digits than its factorization.

66613855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173046.

The product of its digits is 129600, while the sum is 40.

The square root of 66613855 is about 8161.7311276469. The cubic root of 66613855 is about 405.3730343448.

The spelling of 66613855 in words is "sixty-six million, six hundred thirteen thousand, eight hundred fifty-five".