66824641 has 4 divisors (see below), whose sum is σ = 71965012. Its totient is φ = 61684272.

The previous prime is 66824617. The next prime is 66824651. The reversal of 66824641 is 14642866.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14984641 + 51840000 = 3871^2 + 7200^2 .

It is not a de Polignac number, because 66824641 - 2⁹ = 66824129 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66824641.

It is not an unprimeable number, because it can be changed into a prime (66824651) 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, 2570166 + ... + 2570191.

It is an arithmetic number, because the mean of its divisors is an integer number (17991253).

Almost surely, 2^66824641 is an apocalyptic number.

It is an amenable number.

66824641 is a deficient number, since it is larger than the sum of its proper divisors (5140371).

66824641 is a wasteful number, since it uses less digits than its factorization.

66824641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5140370.

The product of its digits is 55296, while the sum is 37.

The square root of 66824641 is about 8174.6339979231. The cubic root of 66824641 is about 405.8001576613.

The spelling of 66824641 in words is "sixty-six million, eight hundred twenty-four thousand, six hundred forty-one".