66666641 has 4 divisors (see below), whose sum is σ = 68217072. Its totient is φ = 65116212.

The previous prime is 66666631. The next prime is 66666643. The reversal of 66666641 is 14666666.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66666641 - 2¹⁴ = 66650257 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (66666643) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 775151 + ... + 775236.

It is an arithmetic number, because the mean of its divisors is an integer number (17054268).

Almost surely, 2^66666641 is an apocalyptic number.

It is an amenable number.

66666641 is a deficient number, since it is larger than the sum of its proper divisors (1550431).

66666641 is a wasteful number, since it uses less digits than its factorization.

66666641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1550430.

The product of its digits is 186624, while the sum is 41.

The square root of 66666641 is about 8164.9642375212. The cubic root of 66666641 is about 405.4800810016.

The spelling of 66666641 in words is "sixty-six million, six hundred sixty-six thousand, six hundred forty-one".