281088991 has 4 divisors (see below), whose sum is σ = 281358000. Its totient is φ = 280819984.

The previous prime is 281088961. The next prime is 281089009. The reversal of 281088991 is 199880182.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 199880182 = 2 ⋅99940091.

It is a cyclic number.

It is not a de Polignac number, because 281088991 - 2¹¹ = 281086943 is a prime.

It is a super-2 number, since 2×281088991² = 158022041722796162, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (281088961) 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, 132931 + ... + 135028.

It is an arithmetic number, because the mean of its divisors is an integer number (70339500).

Almost surely, 2^281088991 is an apocalyptic number.

281088991 is a deficient number, since it is larger than the sum of its proper divisors (269009).

281088991 is a wasteful number, since it uses less digits than its factorization.

281088991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 269008.

The product of its (nonzero) digits is 82944, while the sum is 46.

The square root of 281088991 is about 16765.7087831085. The cubic root of 281088991 is about 655.0602986269.

The spelling of 281088991 in words is "two hundred eighty-one million, eighty-eight thousand, nine hundred ninety-one".