66740281 has 4 divisors (see below), whose sum is σ = 69041700. Its totient is φ = 64438864.

The previous prime is 66740263. The next prime is 66740291. The reversal of 66740281 is 18204766.

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 57229225 + 9511056 = 7565^2 + 3084^2 .

It is a cyclic number.

It is not a de Polignac number, because 66740281 - 2⁷ = 66740153 is a prime.

It is a super-2 number, since 2×66740281² = 8908530215917922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66740221) 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, 1150666 + ... + 1150723.

It is an arithmetic number, because the mean of its divisors is an integer number (17260425).

Almost surely, 2^66740281 is an apocalyptic number.

It is an amenable number.

66740281 is a deficient number, since it is larger than the sum of its proper divisors (2301419).

66740281 is a wasteful number, since it uses less digits than its factorization.

66740281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2301418.

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 66740281 is about 8169.4725043910. The cubic root of 66740281 is about 405.6293238871.

The spelling of 66740281 in words is "sixty-six million, seven hundred forty thousand, two hundred eighty-one".