66642413 has 4 divisors (see below), whose sum is σ = 66901980. Its totient is φ = 66382848.

The previous prime is 66642409. The next prime is 66642419. The reversal of 66642413 is 31424666.

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 41822089 + 24820324 = 6467^2 + 4982^2 .

It is a cyclic number.

It is not a de Polignac number, because 66642413 - 2² = 66642409 is a prime.

It is a super-3 number, since 3×66642413³ (a number of 24 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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 66642413.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66642419) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 129398 + ... + 129911.

It is an arithmetic number, because the mean of its divisors is an integer number (16725495).

Almost surely, 2^66642413 is an apocalyptic number.

It is an amenable number.

66642413 is a deficient number, since it is larger than the sum of its proper divisors (259567).

66642413 is a wasteful number, since it uses less digits than its factorization.

66642413 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259566.

The product of its digits is 20736, while the sum is 32.

The square root of 66642413 is about 8163.4804464762. The cubic root of 66642413 is about 405.4309551741.

The spelling of 66642413 in words is "sixty-six million, six hundred forty-two thousand, four hundred thirteen".