66501555 has 32 divisors (see below), whose sum is σ = 109105920. Its totient is φ = 34577280.

The previous prime is 66501527. The next prime is 66501559. The reversal of 66501555 is 55510566.

It is not a de Polignac number, because 66501555 - 2¹³ = 66493363 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66501559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 144025 + ... + 144485.

It is an arithmetic number, because the mean of its divisors is an integer number (3409560).

Almost surely, 2^66501555 is an apocalyptic number.

66501555 is a deficient number, since it is larger than the sum of its proper divisors (42604365).

66501555 is a wasteful number, since it uses less digits than its factorization.

66501555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 691.

The product of its (nonzero) digits is 22500, while the sum is 33.

The square root of 66501555 is about 8154.8485577600. The cubic root of 66501555 is about 405.1451088009.

The spelling of 66501555 in words is "sixty-six million, five hundred one thousand, five hundred fifty-five".