66155554 has 16 divisors (see below), whose sum is σ = 104596920. Its totient is φ = 31333120.

The previous prime is 66155539. The next prime is 66155597. The reversal of 66155554 is 45555166.

66155554 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 61858225 + 4297329 = 7865^2 + 2073^2 .

It is a super-4 number, since 4×66155554⁴ (a number of 32 digits) contains 4444 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7687 + ... + 13834.

Almost surely, 2^66155554 is an apocalyptic number.

66155554 is a deficient number, since it is larger than the sum of its proper divisors (38441366).

66155554 is a wasteful number, since it uses less digits than its factorization.

66155554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21605.

The product of its digits is 90000, while the sum is 37.

The square root of 66155554 is about 8133.6064571628. The cubic root of 66155554 is about 404.4412433889.

The spelling of 66155554 in words is "sixty-six million, one hundred fifty-five thousand, five hundred fifty-four".