66039745 has 4 divisors (see below), whose sum is σ = 79247700. Its totient is φ = 52831792.

The previous prime is 66039671. The next prime is 66039751. The reversal of 66039745 is 54793066.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54793066 = 2 ⋅27396533.

It can be written as a sum of positive squares in 2 ways, for example, as 31371201 + 34668544 = 5601^2 + 5888^2 .

It is a cyclic number.

It is not a de Polignac number, because 66039745 - 2¹⁵ = 66006977 is a prime.

It is a super-2 number, since 2×66039745² = 8722495839330050, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 66039698 and 66039707.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6603970 + ... + 6603979.

It is an arithmetic number, because the mean of its divisors is an integer number (19811925).

Almost surely, 2^66039745 is an apocalyptic number.

It is an amenable number.

66039745 is a deficient number, since it is larger than the sum of its proper divisors (13207955).

66039745 is a wasteful number, since it uses less digits than its factorization.

66039745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13207954.

The product of its (nonzero) digits is 136080, while the sum is 40.

The square root of 66039745 is about 8126.4841721374. The cubic root of 66039745 is about 404.2051065339.

The spelling of 66039745 in words is "sixty-six million, thirty-nine thousand, seven hundred forty-five".