66872281 has 4 divisors (see below), whose sum is σ = 76425472. Its totient is φ = 57319092.

The previous prime is 66872279. The next prime is 66872317. The reversal of 66872281 is 18227866.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66872281 - 2¹ = 66872279 is a prime.

It is a super-2 number, since 2×66872281² = 8943803932285922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66872251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4776585 + ... + 4776598.

It is an arithmetic number, because the mean of its divisors is an integer number (19106368).

Almost surely, 2^66872281 is an apocalyptic number.

It is an amenable number.

66872281 is a deficient number, since it is larger than the sum of its proper divisors (9553191).

66872281 is an equidigital number, since it uses as much as digits as its factorization.

66872281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9553190.

The product of its digits is 64512, while the sum is 40.

The square root of 66872281 is about 8177.5473706974. The cubic root of 66872281 is about 405.8965678426.

The spelling of 66872281 in words is "sixty-six million, eight hundred seventy-two thousand, two hundred eighty-one".