66440417 has 4 divisors (see below), whose sum is σ = 66777876. Its totient is φ = 66102960.

The previous prime is 66440401. The next prime is 66440447. The reversal of 66440417 is 71404466.

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 46226401 + 20214016 = 6799^2 + 4496^2 .

It is a cyclic number.

It is not a de Polignac number, because 66440417 - 2⁴ = 66440401 is a prime.

It is a super-2 number, since 2×66440417² = 8828658022267778, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66440447) 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, 168434 + ... + 168827.

It is an arithmetic number, because the mean of its divisors is an integer number (16694469).

Almost surely, 2^66440417 is an apocalyptic number.

It is an amenable number.

66440417 is a deficient number, since it is larger than the sum of its proper divisors (337459).

66440417 is a wasteful number, since it uses less digits than its factorization.

66440417 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 337458.

The product of its (nonzero) digits is 16128, while the sum is 32.

The square root of 66440417 is about 8151.0991283385. The cubic root of 66440417 is about 405.0209144308.

The spelling of 66440417 in words is "sixty-six million, four hundred forty thousand, four hundred seventeen".