66538915 has 8 divisors (see below), whose sum is σ = 79890480. Its totient is φ = 53201952.

The previous prime is 66538909. The next prime is 66538919. The reversal of 66538915 is 51983566.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66538915 - 2⁹ = 66538403 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66538919) 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 7 ways as a sum of consecutive naturals, for example, 16356 + ... + 20014.

It is an arithmetic number, because the mean of its divisors is an integer number (9986310).

Almost surely, 2^66538915 is an apocalyptic number.

66538915 is a deficient number, since it is larger than the sum of its proper divisors (13351565).

66538915 is a wasteful number, since it uses less digits than its factorization.

66538915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7301.

The product of its digits is 194400, while the sum is 43.

The square root of 66538915 is about 8157.1388979225. The cubic root of 66538915 is about 405.2209636070.

The spelling of 66538915 in words is "sixty-six million, five hundred thirty-eight thousand, nine hundred fifteen".