66655407 has 16 divisors (see below), whose sum is σ = 109383680. Its totient is φ = 35158752.

The previous prime is 66655387. The next prime is 66655409. The reversal of 66655407 is 70455666.

It is not a de Polignac number, because 66655407 - 2¹¹ = 66653359 is a prime.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66655409) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 121807 + ... + 122352.

It is an arithmetic number, because the mean of its divisors is an integer number (6836480).

Almost surely, 2^66655407 is an apocalyptic number.

66655407 is a deficient number, since it is larger than the sum of its proper divisors (42728273).

66655407 is a wasteful number, since it uses less digits than its factorization.

66655407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 244182.

The product of its (nonzero) digits is 151200, while the sum is 39.

The square root of 66655407 is about 8164.2762692109. The cubic root of 66655407 is about 405.4573038972.

The spelling of 66655407 in words is "sixty-six million, six hundred fifty-five thousand, four hundred seven".