66957281 has 8 divisors (see below), whose sum is σ = 69154560. Its totient is φ = 64792288.

The previous prime is 66957229. The next prime is 66957287. The reversal of 66957281 is 18275966.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66957281 is a prime.

It is a super-2 number, since 2×66957281² = 8966554957825922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66957287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3821 + ... + 12186.

It is an arithmetic number, because the mean of its divisors is an integer number (8644320).

Almost surely, 2^66957281 is an apocalyptic number.

It is an amenable number.

66957281 is a deficient number, since it is larger than the sum of its proper divisors (2197279).

66957281 is a wasteful number, since it uses less digits than its factorization.

66957281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16143.

The product of its digits is 181440, while the sum is 44.

The square root of 66957281 is about 8182.7428775442. The cubic root of 66957281 is about 406.0684706606.

The spelling of 66957281 in words is "sixty-six million, nine hundred fifty-seven thousand, two hundred eighty-one".