66641783 has 4 divisors (see below), whose sum is σ = 71768088. Its totient is φ = 61515480.

The previous prime is 66641761. The next prime is 66641801. The reversal of 66641783 is 38714666.

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

It is not a de Polignac number, because 66641783 - 2⁸ = 66641527 is a prime.

It is a super-4 number, since 4×66641783⁴ (a number of 32 digits) contains 4444 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 66641783.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66641713) 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, 2563133 + ... + 2563158.

It is an arithmetic number, because the mean of its divisors is an integer number (17942022).

Almost surely, 2^66641783 is an apocalyptic number.

66641783 is a deficient number, since it is larger than the sum of its proper divisors (5126305).

66641783 is a wasteful number, since it uses less digits than its factorization.

66641783 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5126304.

The product of its digits is 145152, while the sum is 41.

The square root of 66641783 is about 8163.4418599020. The cubic root of 66641783 is about 405.4296775978.

The spelling of 66641783 in words is "sixty-six million, six hundred forty-one thousand, seven hundred eighty-three".