287975981 has 4 divisors (see below), whose sum is σ = 288108672. Its totient is φ = 287843292.

The previous prime is 287975959. The next prime is 287975993. The reversal of 287975981 is 189579782.

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 287975981 - 2¹⁰ = 287974957 is a prime.

It is a super-2 number, since 2×287975981² = 165860331265824722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (287975881) 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, 63035 + ... + 67448.

It is an arithmetic number, because the mean of its divisors is an integer number (72027168).

Almost surely, 2^287975981 is an apocalyptic number.

It is an amenable number.

287975981 is a deficient number, since it is larger than the sum of its proper divisors (132691).

287975981 is a wasteful number, since it uses less digits than its factorization.

287975981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132690.

The product of its digits is 2540160, while the sum is 56.

The square root of 287975981 is about 16969.8550671477. The cubic root of 287975981 is about 660.3670907059.

The spelling of 287975981 in words is "two hundred eighty-seven million, nine hundred seventy-five thousand, nine hundred eighty-one".