281991997 has 8 divisors (see below), whose sum is σ = 322382016. Its totient is φ = 241628352.

The previous prime is 281991991. The next prime is 281992013. The reversal of 281991997 is 799199182.

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

It is not a de Polignac number, because 281991997 - 2³ = 281991989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (281991991) 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 7 ways as a sum of consecutive naturals, for example, 29538 + ... + 37900.

It is an arithmetic number, because the mean of its divisors is an integer number (40297752).

Almost surely, 2^281991997 is an apocalyptic number.

It is an amenable number.

281991997 is a deficient number, since it is larger than the sum of its proper divisors (40390019).

281991997 is an equidigital number, since it uses as much as digits as its factorization.

281991997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13187.

The product of its digits is 734832, while the sum is 55.

The square root of 281991997 is about 16792.6173361987. The cubic root of 281991997 is about 655.7610151244.

The spelling of 281991997 in words is "two hundred eighty-one million, nine hundred ninety-one thousand, nine hundred ninety-seven".