66561455 has 8 divisors (see below), whose sum is σ = 79978752. Its totient is φ = 53179168.

The previous prime is 66561437. The next prime is 66561461. The reversal of 66561455 is 55416566.

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 66561455 - 2¹⁴ = 66545071 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 4367 + ... + 12336.

It is an arithmetic number, because the mean of its divisors is an integer number (9997344).

Almost surely, 2^66561455 is an apocalyptic number.

66561455 is a deficient number, since it is larger than the sum of its proper divisors (13417297).

66561455 is a wasteful number, since it uses less digits than its factorization.

66561455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17505.

The product of its digits is 108000, while the sum is 38.

The square root of 66561455 is about 8158.5203928163. The cubic root of 66561455 is about 405.2667145252.

The spelling of 66561455 in words is "sixty-six million, five hundred sixty-one thousand, four hundred fifty-five".