281991109 has 4 divisors (see below), whose sum is σ = 294251616. Its totient is φ = 269730604.

The previous prime is 281991079. The next prime is 281991113. The reversal of 281991109 is 901199182.

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 281991109 - 2¹³ = 281982917 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 (281991139) 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, 6130219 + ... + 6130264.

It is an arithmetic number, because the mean of its divisors is an integer number (73562904).

Almost surely, 2^281991109 is an apocalyptic number.

It is an amenable number.

281991109 is a deficient number, since it is larger than the sum of its proper divisors (12260507).

281991109 is a wasteful number, since it uses less digits than its factorization.

281991109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12260506.

The product of its (nonzero) digits is 11664, while the sum is 40.

The square root of 281991109 is about 16792.5908959874. The cubic root of 281991109 is about 655.7603267876.

The spelling of 281991109 in words is "two hundred eighty-one million, nine hundred ninety-one thousand, one hundred nine".