66615445 has 8 divisors (see below), whose sum is σ = 86087736. Its totient is φ = 49192896.

The previous prime is 66615433. The next prime is 66615473. The reversal of 66615445 is 54451666.

It can be written as a sum of positive squares in 4 ways, for example, as 5008644 + 61606801 = 2238^2 + 7849^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66615445 - 2¹³ = 66607253 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 512362 + ... + 512491.

It is an arithmetic number, because the mean of its divisors is an integer number (10760967).

Almost surely, 2^66615445 is an apocalyptic number.

66615445 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

66615445 is a deficient number, since it is larger than the sum of its proper divisors (19472291).

66615445 is a wasteful number, since it uses less digits than its factorization.

66615445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1024871.

The product of its digits is 86400, while the sum is 37.

The square root of 66615445 is about 8161.8285328718. The cubic root of 66615445 is about 405.3762595898.

The spelling of 66615445 in words is "sixty-six million, six hundred fifteen thousand, four hundred forty-five".